JP2790147B2 - Communication protocol between processors for public trunking. - Google Patents

Description

Detailed Description of the Invention Relationship to Related Applications This application is pending and is filed on Jun. 3, 1987, U.S. Patent Application Serial Nos. 056,922 and 057,046.
No. 056,924 and No. 056,923. This application is also related to pending U.S. Patent Application Serial Nos. 085,490, 085,663 and 085,491, all filed on August 14, 1987.

The present invention relates generally to trunk wireless relay schemes.
More specifically, the present invention uses a plurality of operating lines that are allocated for temporary use by individual mobile station radios, while using digital control signals transmitted over dedicated control lines. It relates to the relay system used.

The trunk operation of a wireless repeater is well known. Early trunk schemes used analog control signals, but recent schemes use digital control signals. The control signal is used on a dedicated control line and / or a different operation (voice) line, for various reasons and with different effects. As a typical example of the conventional trunk wireless relay system, although not comprehensive, to name a few, U.S. Patent Nos. 3,292,178, 3,458,664, 3,571,519, 3,696,210
No. 3,906,166, No. 3,936,616, No. 3,970,801
No. 4,001,693, 4,010,327, 4,012,59
No. 7, No. 4,022,973, No. 4,027,243, No. 4,029,9
No. 01, No. 4,128,740, No. 4,131,849, No. 4,184,
No. 118, No. 4,231,114, No. 4,309,772, No. 4,31
No. 2,070, No. 4,312,074, No. 4,326,264, No. 4,3
No. 39,823, No. 4,347,625, No. 4,360,927, No. 4,
No. 400,585, No. 4,409,687, No. 4,430,742, No.
Nos. 4,430,755, 4,433,256, 4,450,573, 4,485,486 and 4,578,815.

U.S. Pat. No. 4,360,927 is an example of a conventional switched line trunking system that avoids using a dedicated control line. Or by performing a handshake with the repeater point controller from the seized "vacant" working line before allowing communication to proceed.

Trunk wireless relaying schemes have many applications in practice and possibly. However, one more important application is the public trunk (PST) scheme. For example, one scheme of trunk wireless repeaters is to provide efficient wireless communication between individual wireless devices in many different agencies.
It can be used advantageously in the whole city area. Each institution can achieve efficient communication between individual devices of different organizations or sub-organizations. (For example, police stations need to communicate efficiently between different devices on their patrol cars, different portable devices assigned to patrol officers, and different criminal devices such as drug investigators. In some cases, it may be important to communicate simultaneously with a predefined group of devices (eg, all devices, all patrol cars, all patrol officers, etc.). At the same time, other institutions (for example,
Fire departments, transportation departments, water departments, emergency / emergency services, etc.)
Similar communication services may be required. As is well known to those skilled in the art of trunk theory, a relatively small number of wireless repeaters are required if they are trunked (ie,
All of the demands within a given geographic area can be efficiently served if they are shared "as needed" among all possible devices.

The potential benefits of trunk trunking for public use are well-recognized and, as a result, the Association of Public Safety Communications Officers Corporation (formerly The Association of Police) An organization known as Communications Officers (APCO) has created a set of highly desirable features for such a scheme, commonly referred to as the "APCO-16 Condition." A complete list and explanation of such conditions can be found in documents known to those skilled in the art.

An advantageous trunk radio relay scheme is described in pending U.S. Patent Application Serial No. 056,922, filed June 3,1987. In the trunked wireless relay architecture described in this U.S. patent application, an RF "control shelf" that receives and transmits radio frequency signals for a particular operating or control line is a microprocessor-based "trunking card." (Hereinafter referred to as GETC, or General Electric Trunking Card)
Is controlled by The trunking card performs the signal processing functions associated with the control shelf and RF lines. 1
A next point controller (eg, a minicomputer) is connected to the various trunking cards, receives digital signals from the various trunking cards, and sends digital signals to the various trunking cards. The primary point controller performs the control functions of this scheme (during normal operation of the scheme), thus recording calls, dynamically regrouping, and coordinating "patches" and other tasks, as well as new calls. Perform more routine control functions such as assigning lines to One or more originating consoles connected to the primary point controller generate messages requesting service of the primary point controller, generate messages sent from the point controller, and The status of the entire system is monitored via messages sent from the controller.

This is a central part of the relay scheme, as the originating console (s) coordinates virtually every communication of this scheme and is often directly involved in handling the communication of the scheme. A mobile station device may call another mobile station device to set up communication between the mobile station devices, but most of the communication traffic handled by this scheme is
Between the originator at the console and the device of the individual or group of mobile stations. The originating console is the "neural center" of the relay system, which coordinates and monitors the operation of the system. Some of the advanced features offered by this relay scheme are automatic, while others require direct manual intervention by the dispatcher. Therefore, reliable and prompt communication of the control signals between the originating console and the primary point controller is of paramount importance.

The present invention provides means for communicating signals between processors in a digital trunk radio frequency relay scheme. More specifically, the present invention relates to a method for communicating signals between a central point controller and an RF line signal processing module, and between a point controller and a wireless relay originating console via a "downlink". Provide equipment.

The above and other features and advantages of the present invention will be more fully understood from the following detailed description of the presently preferred embodiment with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 1A are simplified block diagrams of an overall trunk radio relay system 100 according to an embodiment of the present invention, and FIG.
A more detailed block diagram showing the signal path between the primary point controller and the originating console shown in the figure, FIGS. 3 and 4 show the format of the message transmitted via the downlink shown in FIG. Figures 5 and 6 are flow charts of an example program control process performed by the point controller shown in Figure 2 to send and receive signals to and from the trunking card, and Figure 7 is a point control. 1 and 2 are flow charts of a control process of an example program performed by the trunking card shown in FIGS. 1 and 2 to communicate a signal to the transmitter 410. FIG. 8 shows a signal propagation delay in the downlink of FIG. FIG. 9 is a time diagram, and FIG. 9 is a diagram showing a downlink trunking circuit shown in FIG. 2 for transmitting a signal through the downlink.
10 is an overall flowchart of a control process of an example program executed by the card and the exchange trunking card, FIG.
FIGS. To 18 are more detailed flowcharts of the control steps of the program shown in FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 1.0 Overall Architecture Architecture An example trunk wireless relay system 100 of the present invention is shown generally in FIG. The scheme 100 has at least one (typically many) mobile (or portable) wireless transceiver station 150 and an RF relay station 175. Mobile transceiver station 15
0 communicates with other mobile transceiver stations via the RF link and relay station 175 and / or with a land partner connected to the relay station via a conventional dial land line.

Relay station 175 includes point controller 410, individual trunk circuit transceiver 177, and a multiplexed telephone interconnect network ("switch" or M).
TX) has 179. The point controller 410 is preferably a main digital computer that monitors the overall operation of the relay station 175. In particular, the point controller 410 sends digital signals to a "trunking card" (TC) 400 connected between the point controller and a separate transceiver,
The operation of the RF transceiver 177 is then controlled by receiving a digital signal (FIG. 1 shows only one transceiver 177 and one trunking card 400; There are multiple trunking card / transceiver combinations, one for each RF line on which this relay operates.)

A point controller 410 communicates with one or more outgoing consoles 102 via a "downlink" 103. Downlink 103 is "downlink" trunking card 4
Has 50 and "switch" trunking card 454. The exchange 179 is also connected to an AVL (vehicle location confirmation device) 181 and a CAD (computer support transmission device) 183. System Manager Console / Computer Station
A 416 is connected to the point controller 410 and the switch 179 to enable the system manager to monitor and control the overall operation of the scheme 100.

The remote receiver 187 and associated central / voting device 189 are connected to the trunking card 400 to measure the so-called "RSS1" signal strength at the signal received at the central relay station and at the remote station. The signal level can be based on the stronger of the selected signal levels, thus improving the quality and reliability of the selected received audio.

An RF link ("RF") connects the RF transceiver 177 with the mobile transceiver station 150. The mobile station 150 transmits digitized voice or digital data signals (encrypted and unencrypted) to the relay station 175 via the RF link, and receives such signals from the relay station. Can be done.

In the form shown in the upper left part of FIG. 1, the mobile station 150 has a mobile RF transceiver 152 connected to a control head 154 via a serial digital bus 153. The mobile transceiver can also be connected to the vehicle repeater 156 via a serial bus. A mobile data terminal interface 158 can connect this serial bus to a mobile data terminal (MDT) 162. Separate digital voice protection module 164
Performs encryption and decryption of data on digitized voice signals and / or digital data signals using conventional DES algorithms.

In another form of mobile radio station, shown in the lower left corner of FIG.
Connect to 153. In this format, the mobile data terminal 162
And the associated interface 158 is a serial bus 153 and / or
Alternatively, it can be directly connected to bus 153A (at the output of coupler 166). When using dual control heads 154A, 154B and associated coupler 166, voice protection module 164
Is preferably connected to the bus 153A.

As shown, various groups of individual wireless devices (mobile or portable wireless transceivers) communicate with one another (either inside their own group or, in some cases, externally) via a shared wireless trunk. Outgoing console 102 is relay system 100
Monitor the operation of. If desired, multiple outgoing consoles 102 (one for each separate body of mobile / portable device) and a master or monitoring outgoing console for the entire scheme may be provided.

2.0 Architecture at the Central Point Next, referring specifically to FIG. 1A, at the central point, the transmitting antenna 200 and the receiving antenna 202 (which may have a common antenna structure) are combined with a signal combining / decomposing circuit.
Used with 204,206, which will be apparent to those skilled in the art. The transmitting and receiving RF antenna circuits 200 to 206 individually separate a plurality of duplex RF line transmitting / receiving circuits included in a plurality of RF relay “stations” 300, 302, 304, 306 and the like (typically, there may be 20 such stations). To be configured. The transmit / receive circuits of each station are typically controlled by dedicated control shelves CS (eg, microprocessor-based control circuits), also as generally shown in FIG. 1A. Such control shelf logic associated with each station is the trunking card TC (another microprocessor-based logic control circuit) 400,
Controlled by 402,404,406. Trunking cards 400-406 communicate with each other as well as with a primary point controller 410 via a control link 412.

The primary point controller 410 (and optional support controller if desired) may be a commercially available general purpose processor (eg, a PDP11 / 73 processor with an 18 MHz-J11 chip device). The key "intelligence" and control capabilities of the overall scheme reside in the controller 410, but if the controller 410 malfunctions or otherwise becomes unavailable, the trunking card can be used to continue trunk trunking. 400 to 406
Alternate support or "fail-soft" control functions can be incorporated within. For further details on such failsoft features, see pending U.S. Patent Application Serial No. 057,146.

The console 102 requests the resources of the point controller 410 by sending a message to the point controller via the downlink 103. In response to the console's request for resources, the point controller 410 allocates the requested resources and informs the console 102 via the downlink 103 that the requested resources have been allocated. Therefore,
Point controller 410 can be considered a resource allocator, and console 102 can be considered a resource requester.

For example, the console 102 may depress the console Bushtalk button (the originating operator has requested an RF line), activate / deactivate "simultaneous select", and activate / deactivate "patch"("simultaneous"). The "selection" and "patch" provide a single call request so that the console can select and call the mobile radio transceivers individually or in groups at will. In response, resources can be requested. Since the mobile radio transceiver is capable of requesting an RF line independently of console operation in the preferred embodiment, the RF line assignment message is received by console 102 even when the console does not issue a line request. (Console 102 may monitor all mobile radio communications in the preferred embodiment).

An optional telephone interconnect 414 can be provided to connect to the public switched telephone network. Typically,
A system manager terminal, printer, etc. 416 (along with one or more originating consoles 102) is also provided for management and control of the overall scheme. If desired, special test and alarm facilities 418 can also be provided.

A somewhat detailed view of the point architecture for the communication of control data is shown in FIG. In this case, PD
P11 / 73 controller 410 uses 19.2 kilobits per second (kbp) RS23
It can be seen that it communicates with up to 25 trunking control cards TC that control each heavy duty relay circuit on a separate line via the two serial links 412 (1) -412 (N). In the preferred embodiment, each link 412 is independent of the other links. Another high speed 19.2 kbps bus 420 is used to communicate with switch 457 and hardware supporting downlink 103 to originating console 102.

For each trunk line to be controlled, a 19.2 kilobit data bus 412 is connected to the trunking station attached to this line.
Monitor by 8031 processor in card TC. A TC (trunking card) controls the control shelf CS and the associated repeaters with audio, communication and control buses. The trunking card uses a support serial link (BSL) synchronization line 422 (in the preferred embodiment, this is actually a high speed serial data link and a single wire synchronization line) to provide clock synchronization and " Receive hard-wired input that provides a "fail-soft" indication. This indication of "fail software" indicates that normal control by the central controller 410 is not available and that an alternate distribution control algorithm should be implemented in each trunking card module TC.

In the preferred embodiment, the originating console is a point controller 41.
Typically, it is not placed at the 0 position. This means that the point controllers 410 should be located very close to the RF control shelves CS, which maximize the RF coverage of the repeater transceiver as well as the effective radiated power (erp). As,
This is because it is preferable to place it at a high place (for example, a skyscraper or a high hill or a mountain top). In contrast, the console 102 is typically located in a location where personnel in communication with the mobile station equipment can conveniently enter and exit (eg, a police station, county, or city office). Etc.). Generally, the transmitting console 102 is located at a certain distance from the point controller 410,
Downlink communication path 103 between point controller and console
A part of a land line or a microwave link in the preferred embodiment.

In the preferred embodiment, switch 457 is connected to outgoing console 1
02, including standard telephone exchanges (MTX) that route audio or other signals between standard TELCO lines (not shown) and RF control shelf CS. For example, switch 457
Between the RF control shelf CS and another control shelf, the control shelf and console 102
Audio between the speakers / microphones or between the control shelf and the telephone line.

Switch 457 responds to the digital control messages transmitted from downlink 103 and operates to route this audio path in a conventional manner. The switch 457 has a main processor, which handles all communication tasks on the downlink 103, and the console 102 and the downlink 103.
Performs various functions, including sending appropriate signals during In the preferred embodiment, switch 457 supports several outgoing consoles 102 and sends downlink messages to the appropriate console (or all consoles in the case of downlink messages).

3.0 Interface between Trunking Card and Point Controller 4103.1 Overall Configuration and Operation of Trunking Card RF Trunking Cards 400-408 and Downlink
Further details regarding the construction and operation of trunking card 450 are set forth in pending U.S. Patent Application Serial Nos. 056,922 and 057,046, filed on June 3, 1987.

As mentioned earlier, trunking cards 400-408
Are located at the control shelf locations of the respective repeaters so as to perform the processing of the control line and the operation operation line,
Downlink Trunking Card (DLTC) 450
It is used on the downlink 103 to provide a communication path between the point controller and the exchange 457. Another switch trunking card (exchange switch) located at or near switch 450
TC) 454 exchanges signals between DLTC 450 and switch 457.

Briefly, RF trunking cards 400-408,
The entire structure of DLTC 450 and switch TC 454 is the same in the preferred embodiment. Each of them is a microprocessor-based control module that executes program control software, and that does not communicate directly with the point controller 410 but instead communicates with the exchange 457.
It communicates with the point controller 410 via a 19.2 kbp RS-232 serial link (except 454). Any trunking card T
C is the RF control line trunking
It can operate as any card, RF working line trunking card, downlink trunking card or switch trunking card.

An RF control line trunking card performs signal processing functions associated with the RF repeater acting on the RF control line. RF
The working line trunking card performs the signal processing functions associated with the RF repeater (or digital voice protected land link connecting the point to switch 457) that acts on the RF working line. The downlink trunking card and the switch trunking card perform the signal processing functions associated with the downlink 103, which exchanges messages between the switch 457 and the point controller 410.

In the preferred embodiment, every trunking card stores the program control software needed to operate as a control line, working line, downlink or switch trunking card. When the system 100 is powered on or reset, in a preferred embodiment, each trunking card operates at least initially as a working line trunking card. After power up, the trunking card is instructed by the point controller to be on the control line or downlink.

The point controller 410 can also dynamically reconfigure each trunking card in the scheme 100 to perform control line, operation line or downlink line processing. For example, when the power is turned on, the point controller 410 sends a message to each of the trunking cards 400 to 408, 450,
Inform the respective trunking cards that they should execute software that controls them to operate as RF control lines, RF operating lines and downlink trunking cards. Each trunking card is enabled or disabled by the action of the point and "turns" to the appropriate point controller (i.e., the primary point controller 410 or optional support point controller). Is done. To dynamically reconfigure the trunking card, the point controller 410 sends a format message to the trunking card so that the trunking card is formatted for a particular function (i.e., Actively request (to start execution of related software). For example, if the control line trunking card and / or the associated repeater fails, the point controller 410 will direct the working line trunking card and re-configure it to become the control line trunking card. Can be configured.

The point controller 410 periodically sends status messages to the trunking cards to determine their identification code, mode of operation, and which point controller is being directed.
In response to the message sent from the point controller 410 to the trunking card, the point test function is also performed by the trunking card.

The point controller 410 tests any trunking card individually if a major malfunction occurs in scheme 100,
You can also reset it. In this test mode, the trunking card uses the test pattern selected by the point controller, and the serial interface of the point controller and the hardware of the trunking card are used.
You can try the port. In the downlink trunking card 450, another diagnostic can test the modem that connects the trunking card to the land link 452.

During normal operation, the trunking card sends information messages to the point controller 410 over the high-speed serial data link 412 and executes commands received from the point controller over the same link. Point controller 410
Trunking card 450 and trunking card 400
Through 408, the control function of the system is performed. But
The trunking card is connected via a supporting serial link,
The assisting trunk mode of operation can be performed without intervention from any point controller (master or assisting) (see pending U.S. Patent Application Serial No. 057,046).

3.2 Configuration of serial data link between point controller 410 and trunking card Control line trunking card 400, operating line trunking cards 402 to 408, and downlink trunking card 450 are all independent. Communicates with the point controller 410 via a high speed serial data link 412 of The communication path between the point controller 410 and any (each) trunking card includes an asynchronous serial RS-232C bus. This serial bus message protocol allows for control line, operation line and downlink line processing using both fixed and variable length message packets. This message protocol is also an efficient error recovery scheme in the presence of noise.

Both the trunking card and the primary point controller 410 support the level translation required for the RS-232C communication device.
The serial link 412 between the point controller 410 and each trunking card is full duplex, allowing simultaneous two-way communication between the devices, and 19.2 kbps in both transmit and receive directions. Transmission speed. The configuration and operation of the link 412 (DL) between the point controller 410 and the DLTC 450 depends on the point controller and the RF trunking cards 400-408.
Is the same as any link 412 between them. At link 412,
The data is transmitted in bytes divided into one start bit, eight bits of binary data, and one stop bit. 8-bit binary data is transmitted with the least significant bit first and the most significant bit last.

FIG. 3 shows an example communication message (bytes) used to exchange messages over link 412.
FIG.

Link 412 itself is a three-wire circuit that includes a transmit data line, a receive data line, and a signal ground line. The serial interface of the point controller corresponding to each link 412 is configured as a data terminal device with a 25-pin connector,
2, 3 and 7 are used as grounds for data transmitted from the bus, data received from the bus, and signals, respectively. Next, the electrical configuration of each serial data link 412 will be described in detail.

 RS-232C electrical interface.

 3-wire asynchronous communication: transmit, receive and signal ground.

 Transmit and receive signals are bipolar.

 The minimum transmission level is ± 5 to ± 15 volts.

The maximum output resistance for the transmit driver is 300 ohms.

 The minimum receiving threshold is ± 3 volts.

 Maximum receive input voltage is ± 25 volts.

The receive input impedance is between 3 and 7 kOhm.

The maximum cable length is 25 feet at a data rate of 19.2 kbp.

 The rate of change is up to 30V / microsecond.

3.3 Serial Data Link Protocol On link 412, data is transmitted at a data rate of 19.2 kbp. The bit time is 52.08 microseconds. Upon reception, the bits must be sampled at least x16 clocks and have a stability hit rate of 15 out of 16. One start bit is used and one stop bit is used. 8-bit binary data is transmitted over the link (see FIG. 3). The preferred embodiment does not use the XON / XOFF protocol.

FIG. 4 is a diagram of a frame format used for exchanging data via the link 412. A start-of-frame symbol indicates that the beginning of the identified message block is to be transmitted. It allows the destination device to examine this symbol and decode the following message start symbol. Thus, the start-of-frame symbol defines the beginning of a new message and is also used to achieve frame synchronization in a noisy message environment where bit and message frame errors may occur. In a preferred embodiment,
The frame start symbol is AA (hexadecimal).

If the message start symbol is from the source device to the "destination device" (the "source device" is one of the point controller 410 and the trunking card that sends the message over link 412, the "destination device" The "device" is a device that receives this message). This symbol indicates what type of command or response is being generated by the source device. Point controller 410
The start-of-frame symbol is sufficiently different from any of the message-start symbols used to aid the error detection and correction schemes used in both, and trunking cards.

The number of data bytes in a message changes with the type of message start byte. The data bytes of the message may include command information, response information or data information, as shown in Table 1 below.

The checksum byte symbol is an indication of the checksum for the entire message block. A checksum is generated and detected by forming a negation of the exclusive OR effect of the message start byte and the message data byte. If the checksum byte received by the destination device is the same as the checksum calculated by the destination device, the destination device will typically send an acknowledgment message to inform the source device that a properly formed message has been received. . On the other hand, if the checksum byte received by the destination device does not match the calculated checksum, the previous message from the destination device (eg, by sending a "no acknowledgment" message, or by not sending any acknowledgment message). -Request retransmission of the frame.

In noisy communication media, error in message bits and message frames can occur. Usually, when such an error occurs, the destination device requests a retransmission of the previous message on the source side. The source device retransmits the same frame up to three times in the preferred embodiment.

4.0 Downlink Architecture Referring to FIG. 2, in the preferred embodiment, the point controller 410 is connected to the downlink trunking card 450 via a 19.2 kbp link 412 (DL). The downlink trunking card 450 is a microprocessor-based control module, which in the preferred embodiment is identical in construction and operation to the trunking cards 400-408 (provided that the software it executes is Control this card to perform message processing functions that the RF line trunking card does not).
A downlink trunking card 450 is connected to a 9.6 kbp land link 452 and the other end is connected to a so-called "switch trunking card" 454. Switch trunking card 454 via high speed 19.2kbp link 456,
Connected to the main processor in switchboard 457. Each link 420, 452, 456 is bidirectional in the preferred embodiment;
Both use different digital communication protocols.

The data rate of the (local high speed) link 412 (DL) from the point controller 410 to the downlink trunking card is over the land link 452 between the switch TC 454 and the downlink trunking card 420. Downlink trunking card 450
Must buffer messages received from link 412 (DL) and then retransmit it via link 452 when link 452 becomes available. Similarly, since the data rate of the (local high speed) link 456 (between switch 457 and switch trunking card 454) is higher than the data rate of land link 452 between the trunking cards, the switch Trunking card 454 links the data it receives from the switch
This data must be buffered before transmission over 52. The communication protocol used on link 452 must be as efficient as possible so that the link does not become a "bottleneck" for data transmitted between point controller 410 and switch 457.

Downlink trunking card 450 and switch trunking card 454 are connected to respective links 420, 452, 456.
Since a completely different communication protocol and message format are used, the preferred embodiment does more than simply buffer control signals.

The form used when the downlink trunking card 450 and the switch trunking card 454 communicate with each other is that the mobile station equipment communicates with the control line trunking card 400 and the operating line trunk in order to communicate over the RF line. The format used by ranking cards 402-408 is virtually identical to that described in pending U.S. Patent Application Serial No. 056,922. The message format used on the high speed link 412 (DL) for communication between the point controller 410 and the downlink trunking card 450 is, in the preferred embodiment, a point controller.
Link 412 between 410 and trunking cards 400-408
Is the same as the message format described before used for communication. In contrast, the message format and communication protocol used on link 456 for communication between switch trunking card 454 and switch 457 differs from the format and protocol used for communication between trunking cards. I have. This is because the main processor in the switch uses a completely different message format in the preferred embodiment.

In the preferred embodiment, downlink trunking
Card 450 converts between the message protocol of link 412 (DL) and the message protocol of link 452, and compensates for the difference in data rate between the two links. Switch trunking card 454 has links 452 and
Provides message protocol conversion and data rate compensation for the 456 interface connection. This conversion is performed reliably and efficiently without reducing the overall data rate between the point controller 410 and the converter 457.

Further, in the preferred embodiment, the downlink 403 between the point controller 410 and the console 102 prioritizes messages so that important messages are transmitted in preference to less important messages. Can be done. The message prioritization ensures that the lower data rate of the link 452 does not degrade the overall response time of the scheme, even when the message load on the downlink 103 is very high.

19.2kb using the "Send and wait for approval" protocol
Data is exchanged between switch 457 and switch trunking card 454 via link 456 between the console of switch p and switch TC. If the acknowledgment is not received within 52 milliseconds, the sending device times out and resends the message (after sending the message three times, give up). If the switch trunking card receive buffer queue has more than four messages, even though the message from the console 102 is correctly received, no acknowledgment is sent from the switch trunking card 454 to the console 102 ( This scheme is used to prevent messages from "accumulating" in the exchange trunking card receive buffer.)

The message transmitted over link 456 is in the following frame for transmission.

Management messages do not use source and destination bytes. Each byte is transmitted asynchronously at a rate of 19.2 kbp, using one start bit and one stop bit (10-bit symbol).

Link 456 between console and exchange TC and link 412 between point controller and downlink trunking card
Both data rates of (DL) exceed the speed of land link 452. In addition to other messages, land links
An acknowledgment message must be transmitted via 452. Buffers are provided in downlink trunking card 450 and switch trunking card 454 to facilitate message flow and maximize data transmission rate over land link 452. Console 102
When the buffer holding the message to be sent to the point controller 410 from the console 102 becomes nearly full, the switch 102 delays the approval of the switch trunking card 454 for the message received from the console 102.
Message flow from the to the point controller can be slowed.

Emergency console message "clutches" in switch trunking card buffer, point controller 410
In order to reduce the risk of not being promptly communicated to the exchange trunking card 454,
The message received from the console 102 can be transmitted.

(1) Retransmission packet (first) (2) Acknowledgment message (second) (3) Control line message (third) (4) Operating line message (fourth) (5) Patch message (fifth) ( 6) Management message (final) When the receive buffer of the downlink trunking card 450 is full, the downlink trunking
By delaying the acknowledgment of the message sent from the card back to the point controller, the overflow of the message generated by the point controller 410 is prevented. Packets requiring acknowledgment and acknowledgment messages are always placed ahead of other messages in the buffer on land link 452
Is transmitted via

FIG. 8 is a schematic illustration of the estimated transmission delay over the downlink 103 for a simple group of calls with no activity on the downlink before sending the message. If all callers have requested the call at the same time, the downlink sends requests to the point controller at the rate of one request every 15 milliseconds. Therefore,
The processing time of 26 ms in the preferred embodiment of the point controller 410 is a marginal delay, and the downlink 103 sends messages to the point controller 410 at a rate faster than the point controller can handle. Can be done.

5.0 Types of Downlink Messages Messages transmitted over the downlink 103 can be classified into two main types: (1) "global" messages and (2) "management" messages.

5.1 Global Downlink Messages Global messages are messages that originate from switch 457 and are to be received by point controller 410 or are transmitted by point controllers as received by the switch. That is,
All global messages propagate along the entire downlink 103 and are used to convey information between the point controller 410 and the switch 457. When a global message is received, either at the DLTC 450 or at the switch TC 454, after it has been converted (as described below), either at the point controller 410 or at the switch 179, as ultimately received, Pass the message along the downlink 103.

Examples of "global" messages are a message from the console requesting the point controller to allocate a line and call the individual or group of mobile transceivers, and a point control to inform the console that the line has been unlocked. This is a message from the container.

In the preferred embodiment, there are three types of global messages:
Operating line messages, control line messages and patches
There is a message. As will become clear later, there is a direct relationship between the control and working line downlink messages and the messages sent on the control and working RF lines. A "patch" global message has no corresponding RF message, which is used to limit and control a particular "patch" group (e.g., a console operator may temporarily and individually and / or group mobile transceivers). Is limited to members of the "patch" group so that the entire patch group can be called using a single console call command.)

5.1.1 Control line global downlink message The downlink control line message corresponds to the signal that the RF line trunking card should (or has) transmitted over the RF control line.

In the preferred embodiment, mobile stations that are not actually participating in active communication on the active line monitor the control line and wait for instructions. To access the working line, the device of the mobile station sends a general request via the inbound control line of the system, and the point controller 410 responds by responding via the control line relay trunking card 400. To send a line assignment message on the outgoing control line (this line assignment message indicates that the mobile station equipment should retune to the assigned working line). Similarly, if the dispatcher of console 102 wants to contact a particular mobile station device, the dispatcher inputs a line request message. In the preferred embodiment, this message is processed by the point controller 410 in much the same way that the point controller handles line requests originating from mobile stations.

Downlink messages originating from the console relating to control line activity are categorized as "control line" downlink messages, and messages originating from point controllers relating to both the control line and the console are Classified as a "control line" message. Such downlink control line messages include, for example, messages originating from the console 102 requesting that a group of mobile station devices or individual mobile station devices retune to the operating line, and A message sent by the point controller 410 to inform the console of the successful assignment of the working line to the device or group, or to indicate the mobile station's device request for communication with the caller, Includes a message that informs the console of a change in the state of the working line assignment (eg, release of the line key or change of the working line frequency). For example, a "point id" message can be classified as a global control line message.
This is because the RF control line trunking card 400 controls its associated RF repeater and, in the preferred embodiment, sends similar messages over the RF control line.

5.1.2 Working line global downlink messages Downlink working line type messages are directly related to the working line activity. The working line global message typically corresponds to each working line message that the point controller sends over the RF working line for the switch (and console) to continuously update with the working line status. , Typically from point controller 410, to switch 179. One example of a global operating line message is a key release message transmitted by the mobile station device 150 via the operating line.

5.1.3 Patch Global Downlink Message The preferred embodiment scheme 100 has "patch" capability, so that the originator has the flexibility to temporarily and individually call the group of mobile station devices a "patch". Can be configured. In a preferred embodiment, the mobile station device comprises:
It is pre-programmed to respond to scheduled individual and group identification codes transmitted over the control line. For example, a mobile transceiver mounted on an undercover car carrying a criminal may have a unique device identification code for all murderer mobile station devices, another group identification code for all police equipment, and its identification. Can respond to the individual call identification code corresponding to the device.

However, in some cases, all murder criminal, all police equipment in a particular police station, and any individual criminal investigation device are called simultaneously without calling all police devices. May be necessary. A preferred embodiment is
The originator can specify a temporary "patch identification code" corresponding to the collection of group and / or individual mobile station devices to be included in the call. Like Once this "patch identification code" is specified, the dispatcher can call all the devices in the specified collection by pressing a single patch send button on console 102. At this time, the primary point controller 410 automatically controls the control line trunking card 400 to send individual and group appropriate call messages over the control line, and Of all the mobile station devices in the group of the mobile stations to tune to the vacant operation line. The downlink supports certain patch commands that allow the console 102 to create, modify, and disable such special patches.

5.2 Management Downlink Message The management downlink message is a message that does not propagate over the entire length of the downlink 103 between the point controller 410 and the exchange 450. These management messages are
An "overhead" message used to keep the downlink 103 operating properly and does not convey any useful information between the point controller and the switch 457. The management message is used, for example, to query the status of the downlink and to acknowledge that the downlink message has been correctly received.

For example, one management message may have one trunking
It originates from the cards 450, 454 and is to be received by the other trunking card. Other administrative messages are generated by the point controller 410 and are not DL 457 but DL
It should be received by TC 450 and / or switch TC 454. Still further, management messages are generated by switch 457 and are to be received by switch TC 454 and / or DLTC 450 rather than point controller 410.

An example of a management message is a DLTC to acknowledge that the point controller has correctly received a previously transmitted data byte.
An approval message sent from 450 to the point controller 410,
And from the point controller to the DLTC and switch TC 454 to "form" the trunking cards into the operating mode they need to support downlink communications.
Is a message that causes

6.0 Downlink Data Conversion The protocols used on the links 420, 452, 456 are all different from each other in the preferred embodiment. For example, a circuit link from a point controller to downlink trunking
412 (DL) data is transmitted with the least significant byte and least significant bit first. On land link 452, data is transmitted most significant byte and most significant bit first. On link 456 between switch trunking card 452 and switch 457, the most significant byte is transmitted first,
Each byte is transmitted least significant bit first.

The downlink trunking card 450 of the preferred embodiment converts between the data format of link 412 (DL) and the data format of link 452. Similarly, switch trunking card 454 uses link 452 data format and link 456
Convert between data formats. These transformations are relatively straightforward. For example, many such conversions can be performed by storing the received data in a buffer memory in the order received, and then reading the stored data in another order. Other conversions (eg, conversions performed by switch TC 454 between link 456 and land link 452) are "MID"
It requires a mapping between the operation code (used by switch 457 and console 102) and the corresponding "GETC" operation code (used by downlink TC 450, point controller 410 and RF trunking cards 400-408).

Tables 3 to 10 below show the field-by-field conversions performed on the downlink 103 for various types of global messages. Field definitions are provided in Appendix I, and the corresponding message format is defined in the following description.

6.1 Data conversion of global messages originating from a point There are three types of global messages originating from a point. That is, a single slot control line message, a two slot control line message, and an operation line message. For each type of message, the table below shows links 420, 45
It shows how types, bits and nibbles move between 2,456.

6.2 Data Conversion of Global Messages Originating at the Console The following table lists the data conversions performed on global messages originating at console 102 (switch 457).

7.0 Example of Program Control Process Next, the point controller 41 is used to communicate messages between the point controller and the console 102, and between the point controller and the RF line trunking card via the downlink 103.
0, control processes of an example program executed by the RF trunking cards 400 to 408, the DLTC 450, the exchange TC 454, and the exchange 457 will be described.

7.1 Interaction of Point Controller 410 with Trunking Card The manner in which the point controller 410 interacts with each of the various trunking cards will now be described.

When the power is turned on, the point controller 410
A message is sent to the trunking card 450 to indicate that the trunking card should be running appropriate software (eg, control line, operating line or downlink software). When configuring the downlink trunking card 450, the point controller informs the trunking card how many active lines are in the scheme 100 and, if necessary,
Instructs the downlink trunking card to direct the communication to the support point controller. The primary point controller 410 periodically sends a status request to the downlink trunking card 450 to determine its identification code, operating mode and which point controller is being directed.

The primary point controller 410 occasionally counts the broadcast message count to the downlink trunking card 450 to inform the number of broadcast messages sent from the point controller to the downlink trunking card. Send. The trunking card, as in all of scheme 100, is independently responsible for tracking the current scheme state information, and the broadcast message count determines whether the various trunking cards have been correctly updated for the current scheme state. Help you decide. The broadcast message count is incremented after every broadcast type message received.

Whenever a bit or frame error occurs on the link 412 (DL), the test controller 410 retransmits the last message to the downlink trunking card 450 simply by not accepting the message. Can be requested. Point controller 410 uses method 1
If a major malfunction occurs at 00, the downlink trunking cards 430 can be individually tested and reset. In this test mode, the downlink trunking card 450 uses a test pattern selected by the point controller to connect the modem (link 45
2), point controller serial interface and trunking card hardware port to be able to try.

Outbound downlink line communications are handled by the point controller 410 with the downlink trunking card 450 acting as a buffer device. On the receiving side, a status response is sent by the downlink trunking card 450 to the point controller 410 so that the point controller can determine whether the downlink trunking card is operating properly. . Inbound downlink line messages from originating console 102 are buffered by downlink trunking card 450 and sent to point controllers. The message is transmitted in the form of a frame via the link 412 (DL).
Each symbol transmitted or received over link 412 (DL) includes the 10-bit RS-232C serial data packet stream shown in FIGS. 3 and 4 (and described in detail above).

If the downlink trunking card 450 requests three subsequent retransmissions from the point controller 410 after the point controller has transmitted the synchronization sequence,
The trunking card enters a failsoft operating mode. The point controller 410 is used for downlink trunking,
Whenever the card must be requested to retransmit the frame more than twice, it sends the synchronization order.

7.1.1 Message Transmission on Link 412 FIG. 5 is a flowchart of an example program control process (state) performed by the point controller 410 to transmit a message frame over the link 412,
The synchronization symbol (block 504) is tracked by the trunking card. The point controller 410 starts the frame start symbol (block 5).
06), send a message start symbol (block 508) and a variable number of message data bytes (block 510). After the message data, point controller 410 transmits the checksum symbol (block 512) and waits for the next frame that needs to be transmitted. If a checksum error is detected by the trunking card, the message will not be acknowledged and the point controller 410 will resend the message.

FIG. 7 shows the steps performed by the trunking card to send a message to point controller 410 via link 412. These steps are essentially the same as those performed by the point controller to send the message (see FIG. 5).

7.1.2 Point controller 4 for messages sent from DLTC 450
Fig. 6 shows link 412 (DL) from trunking card
4 is a flowchart of an example program control process performed by the point controller 410 to receive a message transmitted via the. The point controller 410 has memory to use as a queue / buffer for received messages, and in the preferred embodiment, waits for a frame symbol (hex "AA") indicating the beginning of a new message frame (decision block 522). ). Upon receiving this frame symbol, point controller 410 looks for the message ID byte (decision block 524), and then looks for a variable number of data bytes (the number of bytes has been determined to be the start symbol) (decision block 526). ), Then looking for a checksum byte indicating the end of the message (decision block 528). Once the checksum bytes are received, point controller 410 calculates a checksum based on the received message symbols and compares the calculated checksum with the received checksum to determine if they correspond. .

If the received checksum and the calculated checksum correspond, a "good" message has been received and the point controller
410 begins processing the message (block 530). On the other hand, if the test performed by any of decision blocks 524 through 530 is not successful, point controller 410 abandons, logs an error, and waits for the next frame start symbol (block 52).
2).

7.2 Steps Performed by TLDC 450 and Switch TC 454 FIG. 9 is a simplified flowchart of the control steps of an example program implemented by scheme 100 for communicating data over the downlink. A series of operations shown on the left side of FIG.
L), downlink trunking card 450, land link 452, switch trunking card 454 and link 45
6 to the console 102. The steps shown on the right side of FIG. 9 are used in the preferred embodiment to communicate messages from the console 102 to the point controller 410 via the downlink 103. The steps shown in the upper half of the flowchart in FIG. 9 are the downlink trunking card 450
And the steps shown in the lower half of this figure are performed by switch trunking card 454.

When the point controller 410 generates a message and sends it to the downlink trunking card 450 via link 412 (DL), the downlink trunking
The card first executes the receive logic routine (block 602) to actually receive the message. Next, the downlink trunking card 450 implements a message processing routine (block 604) to parse the received message and determine if the message is correct. In particular, block 604 tests whether the received message is a management message that the downlink trunking card must respond to or a message to send to the console 402 over the downlink. If the message is a management message that requires a response, the downlink trunking card creates a response and places it in the transmit buffer (block 60).
6) to be sent back to the point controller (block 60)
8).

If the message received from the point controller is a "good" message and should be communicated to switch trunking card 454, the message is buffered in the transmit buffer (block 610), and block 612 causes the land link 452 to be transmitted.
To send over. Switch trunking card 454 executes block 614 to receive the data packet transmitted over link 452 and determine if the received message was in the correct form and was received without error.
If the received message is a "good" message, block 614 places an acknowledgment message in the switch trunking card's transmit buffer priority queue (block
616). Thereafter, switch trunking card 454 processes the received message (block 618).

If the received message is a management message that requires a response from switch trunking card 454, the trunking card places the management message response in its transmission priority queue (block 616). On the other hand, if the incoming message is to be sent to console 102,
Switch trunking card 454 places this message in an internal receive buffer (block 620) and sends the message to console 102 via link 456 (block
622).

In response to the message received by switch trunking card 454 from console 102 via link 456, the switch trunking card executes the receive logic routine (block 624) (eg, buffer (block 620)).
Acknowledgment of the received message, if appropriate. If the message is an administrative message that requires switch trunking card 454 to perform some diagnostic routine,
A diagnostic routine (or other processing) is performed (block 626). For example, console 102 may request switch trunking card 454 to transmit its format, so the trunking card puts the format information into its buffer (block 620). On the other hand, if the received message is to be sent to point controller 410, switch trunking card 454 places the received message in its priority queue at a location determined by the type of message (described above). Put (block
616). Switch trunking card 454 blocks 628
To remove the message from the priority queue and send it to the downlink trunking card 450 via the land link 452.

When the downlink trunking card 450 receives a message originating from the console via the land link 452, it is the receive logic routine (block 630).
To ensure that a "good" message has been received and acknowledge the reception by placing an acknowledgment message in its transmit buffer (block 610). The downlink trunking card 450 then processes the received message (block 632) and, if the message is a managed message, the switch trunking card 450
A response is sent back to 454 (block 612). If the received message is to point controller 410, downlink trunking card 450 places the message in its buffer (block 606) and passes it to link 412 (DL).
To the point controller (block 608).

7.2.1 Transmission of Message from Point Controller 410 to Switch 457 FIG. 10 is a more detailed flowchart of block 602 of FIG. The routine shown in FIG.
To receive and retrieve messages sent over link 412 (DL) from
Implemented by card 450.

First, determine whether the downlink trunking card 450 has received a start symbol (block 65).
0). (In the preferred embodiment, a start symbol is used to indicate the beginning of a frame of a message transmitted over link 412 (DL).) If no start symbol has been received, DLTC 450 starts. Wait for the sign. Once the start symbol is received, DLTC 450 determines whether the "GETC" code is valid (block 652). (That is, test whether the received message is a valid message.) If the received GETC code is invalid, tabulate the error (the tabulated error is a point controller or console for downlink behavior). Used later to inform 102). If the GETC code is valid, the DLTC 450 determines from this code how many more data bytes it is expected to receive, and then retrieves the transmitted data byte following the GETC code And counting the number of symbols to determine when the message is over (block 65)
8). If the maximum delay expires before receiving the required number of symbols, DLTC 450 will signal an error and wait for the next message. On the other hand, if the entire message is received before the maximum delay expires, the DLTC calculates a checksum based on the received symbols and compares the calculated checksum with the contents of the received checksum byte (block 662). . If the calculated checksum and the received checksum do not correspond, a transmission error has occurred and the entire received message is discarded,
Tabulate the errors. On the other hand, if the checksum checks show that the message was received correctly, the message is processed by the "Process Good Message" block 604, and D
LTC 450 waits for next message (decision block 6
50).

If the test at block 662 indicates that the received message is good, the message is processed by message processing block 604. A detailed flowchart of this block is shown in FIG. Block 675
685 decode the "GETC code" of the received message to determine what type of message was received.
Certain messages require an immediate response from DLTC 450 and other messages are to be transmitted by DLTC over link 542. G (from the test in block 675)
If the ETC code is 01, the point controller 410 requests the DLTC 450 to configure the format (e.g., scheme 10
When power is first applied to 0 or when the system is reset). Decision block 687 determines bits 7 and 6 of the message.
Test whether both are set. If these bits are set, ignore the command (this is unless the downlink trunking card has already configured and configured for downlink operation). First, the routine of FIG. 9 is not executed). If both bits b7 and b6 are not set in the newly received message, the point controller 410
Has requested that some other type of trunking card be configured, and a configuration process is performed to implement the change (block 689).

Block 677 determines whether the GETC code of the newly received message is a control line 2 slot message. If you receive these types of messages,
The downlink trunking card must prepare this message for transmission over the link 452 to the switch trunking card 454. Downlink trunking card 450 computes the normal BCH error check field (block 691). Link 412 (D
The messages in L) are protected by error checking by checksums, but to reduce the number of messages that need to be retransmitted over the land link, the land link 452
In order to protect the data transmitted over the BCH, more powerful BCH error checking and correction algorithms are used.

After this, the downlink trunking card 450
Searches its destination FIFO buffer 610 for the last buffered one-slot control line message (block 693). Downlink trunking card 450 separates data into packets and land link 452
To send over. Each packet has at least one message, preferably two messages. The packet is long enough to contain an independent control line one slot message or two working line messages. In the preferred embodiment, each packet has the same type of message. For example, one packet has two 1
Has a slot control line message and another packet is 2
One packet may have one working line message, but none of the packets has a control line message and a working line message. In the preferred embodiment, the two messages are in the same packet. Block 693 searches the downlink trunking card's transmit buffer to locate the last packet containing the control line message as the buffered packet, and decision block 695 determines the second of this message packet. Determine if the message slot is full. If the second message slot is not full, the newly received control line message is stored in this second slot (block 697). If the second slot is full, create a new message packet and assign a packet number to the new message (block 699), and the second slot of this new packet accepts another control line message for this packet. Is set to indicate that it can be done (block 701). In the preferred embodiment, each packet to be transmitted is a packet number (just an arbitrary number generated sequentially to uniquely select the packet and acknowledge receipt of the individual packet). ) Is assigned. Once a packet is created by blocks 699 and 701, the packet is stored in a first-in first-out buffer at block 702 (block 61 shown in FIG. 9).
0), awaiting transmission via link 452 by block 612 of FIG.

If block 679 determines that the received message is a working line message, then execute blocks 703-713 (which are very similar to blocks 691-701) to prepare the working line packet for transmission. Then, the packet is stored in the FIFO transmission buffer (block 702).

If the newly received message is a control line 2 slot message (as determined by block 681), it fills the entire packet. Calculate the BCH error check field for it (block 715), assign it a packet number (block 717), and then buffer the 2-slot message packet for transmission (block 70).
2).

If decision block 683 determines that the newly received message is a test message, decision block 719 tests whether a modem test has been requested. If the point controller 410 has requested a modem test, the modem generates a dot through a modem test routine (not shown). Otherwise, ignore the message.

If the GETC code of the newly received message indicates that the message is a status request message (from the test of block 685), then decision block 721 returns any type of status information (current status, configuration request, broadcast count or activity request). ) Is requested. An activity request (represented by bits b1 and b0 being set respectively) is transmitted by the downlink trunking card 450
Send a message from. All other combinations of these bits cause the downlink trunking card 450 to send specific status information back to the point controller 410 (block 723).

The first-in first-out buffer 610 shown in FIG. 9 is constructed in a preferred embodiment in a conventional manner. That is, this buffer acts as a message queue in the internal memory of the downlink trunking card 450 such that the first message stored in the queue becomes the first message to be dequeued. Just an area. Before any packets generated by block 604 are transmitted, block 610 sends all retransmission packets and acknowledgment messages.

Once a message has entered this FIFO buffer, it is transmitted by the transmit logic routine 612, which is detailed in the flowchart of FIG. This transmission logic routine 612 actually sends the message over the land link 452 and records any messages already sent that are not acknowledged by the switch trunking card 454 and must be retransmitted.

Block 730 attempts to retrieve the "oldest" message in the downlink trunking card's transmit buffer. If the transmit buffer is empty, the downlink trunking card 450 transmits a 4-byte dot pattern (alternate binary value bits, or 101010) (block 732). On the other hand, if there is a message to be sent, the DLTC 450 will use the word sync barker code symbol (block 734) and the GETC code corresponding to the packet (block 7).
36), and then determine if a packet or message is being transmitted (decision block 738). If a packet is to be sent (rather than an acknowledgment message or other form of management message), the packet number is sent first (block 740), followed by the contents of the first message slot and the corresponding BCH error check code. Send (blocks 742,744) followed by the contents of the second message slot and the corresponding BCH code (blocks 746,748). (Decision block 745 determines whether the second slot actually contains a message. Blocks 702 and 744 transmit the contents of the first slot regardless of whether there is a message in the second slot. If the data being transmitted is a message rather than a packet, the message is transmitted with the corresponding checksum code (block 752) (since only the data packet, and not the message in the preferred embodiment, is protected by the BCH code). (Block 750).

Thereafter, the downlink trunking card 450 stores the message in the message acknowledgment queue (block 754) and determines whether any messages in the message acknowledgment queue have been acknowledged (the contents of the received message acknowledgment queue). To determine if the packet number field of any acknowledgment message received from switch TC 454 matches the packet number field of any message in the acknowledgment queue). Remove all acknowledged messages from the message approval queue (block 756). Next, DLTC 450,
It is determined whether any messages have been in the message acknowledgment queue for more than 30 milliseconds (decision block 758). (This test can be performed, for example, by storing the real time together with the messages as they are stored in the message acknowledgment queue. The real time corresponds to the time that the messages are stored in the queue. Then compare the stored real time field of each message with the current real time.) If any message has not been acknowledged for more than 30 ms, it has already been retransmitted three times. If not, resend it via DLTC. Increment the retransmission counter associated with the entry in the approval queue every 30 ms or more (block 760) and compare all incremented retransmission counters with a value of 3 (decision block 762). . Downlink trunking card 4
50 "discards" messages that have already been retransmitted three times, but have not yet been acknowledged, and stores the error code for later referrals from point controller 410 (block 76).
Four). On the other hand, messages that have not been acknowledged for more than 30 milliseconds and have not been retransmitted three times are removed from the message acknowledgment queue (block 764) and retransmitted by blocks 734 through 748.

FIG. 13 illustrates a receive logic routine 6 executed by switch trunking card 454 to receive data packets and messages transmitted over land link 452.
14 is a detailed diagram. Decision block 775 arrives
The code (word sync pattern) is searched to determine when an incoming message is present on link 452. When the Barker Code arrives, the switch trunking card 454
It is determined whether the GETC code in the received packet is valid (decision block 777), and then the packet number is searched (decision block 779). If the packet number is not included in the received data, it means that the message was received instead of the packet, the message is stored (decision block 781), and the checksum of the received message is checked (decision block 783). If the checksum calculated by switch trunking card 454 corresponds to the checksum field of the received message, the received message is considered to have been received without error and a good message processing block
Further processing by 618. If a checksum error is detected, discard the received message (block 785),
The error is recorded (block 787).

If the received data has a packet number, switch trunking card 454 determines whether the packet has already been acknowledged (decision block 787). In the preferred embodiment, DLTC 450 retransmits the same packet number with any messages it retransmits. In some cases, switch trunking card 454 correctly receives the packet and sends an acknowledgment, but downlink trunking card 450 does not receive this acknowledgment and therefore sends the same packet again. Decision block
The 787 tests this condition so that it does not waste time processing messages already acknowledged and processed, and generates another acknowledgment message for the received packet (block 789). To the downlink trunking card 450 via link 452.

If you have not received the received packet correctly before,
Temporarily store the message it contains (block 791,
797), and analyze the BCH error check code it has in a conventional manner (decision blocks 793,799). If the BCH algorithm indicates that the packet was received correctly, the received message is further processed by block 618 in FIG. However, if a message is received incorrectly, the entire packet is discarded (block 78).
5) Do not approve the message and force the downlink trunking card 450 to resend the message. With every packet and every message received correctly, the downlink trunking card 450
Formulates a message count (block 801) and sends an acknowledgment message to the downlink trunking card (block 789).

The “good” message processed by the receive logic routine 614 is replaced by the “good message processing” routine (No. 9).
Sent to block 618). A detailed flowchart of this routine is shown in FIG. Routine 618
Determines the type of the newly received message by testing the GETC code of the message (blocks 825 to 835). If the received message is an acknowledgment message (as determined by block 825), it is further processed by the send logic block 628 (block 837).

If the received message is a two-slot control line message (indicated by the GETC code = 08 in block 827), the switch trunking card 454 will allow the console 102 to understand the received GETC code (in this case,
MID = GETC = 08) (block 839) and the switch trunking card uses
Setting up a message to be sent to console 102 begins by freeing some bytes of the temporary storage buffer (block 841).

If the GETC code received = OD (indicating a one-slot control line message), switch trunking card 454 analyzes the rest of the message to determine what type of one-slot control line message was received. At the same time, the MID code must be determined to an appropriate code corresponding to this message. (MID = 9 for device key connection message, MID = 10 for key release / line D assignment message, group ID to patch ID
MID = 12 for assignment message of ID, MID = 13 for assignment message of individual ID to patch ID, point ID
MID = 14 for the message or MID = 15 for the line update message. 6.) The number of data bytes to keep free for any control line 1 slot message is 6 (block 845).

If the received GETC code = 19 (indicating an operating line message), the exchange trunking card
454 sets MID code 11 (work line message) (block 847), leaving five data bytes for the work line message (block 849).

For control line and operating line messages, switch trunking card 454 adds the source and destination code (block 851) and inserts the message itself (block 8).
53) Calculate the checksum (block 855), and pass the "assembled" message thus switch trunking
The message is "assembled" by storing it in the card's transmit FIFO buffer (see block 620 of FIG. 9).

If the received GETC code = FB (test message), the response (message request) is simply that the exchange trunking card is the downlink trunking card 45
It is stored in a priority queue 616 that is used to put messages back to zero. If the received GETC code = 07 (status request message), switch trunking card 454 tests whether the requested status information is for downlink activity (decision block 86).
1). If downlink activity information is requested, this information is stored in the priority queue 616 for transmission back to the point controller 410.

The block 618 of FIG. 9 is a switch trunking card that communicates messages that must be transmitted to the console 102.
454 is stored in the FIFO buffer 620. Block 62 in FIG.
A second send logic routine (detailed in the flowchart of FIG. 15) retrieves the message from this buffer and sends it to the console 102 via link 456. Fetch this message from the FIFO buffer (block 87
5) Transmit via link 456 between console and switch TC (blocks 877-885). Next, routine 622:
It determines whether the message sent to console 102 has been acknowledged (decision block 887). A message that remains unacknowledged for more than 50 milliseconds (by the test of decision block 889) will be retransmitted if it has not been transmitted three times already. If so, switch trunking card 454 "discards" and records an error (blocks 891-895).

If the console 102 receives more messages from the switch trunking card 454 than can be handled at a given time, it will stop acknowledging the messages sent to it and will force the switch trunk. Have the ranking card wait 50 ms and then resend the message. This allows the console 102 to slow down the downlink transmission rate so that it has enough time to process the received message.

7.2.2 Transmission of Message from Switch 457 to Point Controller 410 Of course, console 102 can initiate its own message and send that message to switch 400 via switch 457 and downlink 103. Once console 102 composes a message, the console passes this message through switch 457 and switch trunking card 454 via link 456 between the console and switch TC.
Send to Block 624 of FIG. 9 accumulates console messages and acknowledges them. If necessary, transmission of console messages on the downlink is slowed to match the lower data rate of the land link 452. A detailed flowchart of the receive logic routine 624 is shown in FIG.

Switch trunking card 454 looks for a start symbol indicating the beginning of a new message (block 902) and then determines whether the MID code contained in the message is valid (decision block 904). If the MID code is invalid, an error is signaled (block 906) and the switch trunking card waits for the next message. If the MI code is valid, switch trunking card 454 determines from this code how many symbols following this code should be expected and sets a maximum delay period according to the number of symbols (block 908). . (This maximum delay period is the maximum period by which the switch trunking card should have received the entire message.) If the required number of symbols have not been received by the time this delay period expires (Decision blocks 910,912), ignore the received message,
The error is recorded (block 906). If the entire symbol of the message has been received before the delay expires, a check sum is checked (decision block 914) to determine if the newly received message is error free. If the received message has a checksum error, record the error (block 906) and ignore the message. If there is no error in the received message, the message counter is incremented to indicate that the message was received (block
916), send the message to block 626 in FIG. 9 for "good message processing". Meanwhile, switch trunking card 454 determines how many messages are stored in priority queue 616 (block
618) If more than four messages are stored, 1 before acknowledging the received message (block 922).
Delay for 5 ms (block 920). The received message is acknowledged by storing the corresponding acknowledgment message in a FIFO buffer managed by block 622 of FIG. 9 (block 922). FIGS. 17A and 12B together show details of the "handle good message" routine (block 626 of FIG. 9) performed by switch trunking card 454 to process messages received from console 102. It is a flowchart. Block 626
Also manages a priority queue (used to order messages sent to the point controller 410 over the downlink). As previously described, in a preferred embodiment of the present invention, one way to compensate for the lower data rate on land link 452 is to prioritize the messages so that the more important messages are less important. Make sure that they are transmitted before insignificant messages.

Switch trunking card 454, under control of message processing routine 626, first determines the type of message to be transmitted by testing the MID code associated with the message (blocks 925-933). The acknowledgment message (MID = 04) is processed by simply sending the acknowledgment message to the send logic routine 622 (blocks 925, 935). The control line individual and group call messages (MID = 24 or MID = 25) calculate the BCH error check / correction field (block 937) and have the control line message (if any) already queued. The message is processed by putting this message in the second slot of the current packet (blocks 939,941,943). Switch trunking card if no control packet with second free slot in priority queue
454 sets new packet with GETC code = 08 (1 slot control line) (block 945), packet number (block 947) and second free slot (block 949), then waits for priority for new packet Store in a matrix (block 951). Finally, the counter which keeps track of the number of entries in the priority queue waiting to be transmitted is incremented (block 953) and the switch trunking card waits for the next message to be processed.

If the MID code of the newly received message indicates that this message is a working line message (from the test of block 929), then perform blocks 955 through 967 to calculate BCH error check information and run the working line message. Put in the second slot of the line data packet (if any) and, if necessary, form a new working line data packet. Block 969 queues this new working line data packet in the priority queue after the last working line packet (so that it is sent only after all control line packets and acknowledgment packets have been sent). (After the oldest working line data packet).

If the new message is a patch message (as seen by decision block 931), switch trunking card 454 must transmit a packet that is relatively long compared to other packets transmitted over the downlink. . Patch messages may be up to 16 packets long in the preferred embodiment, and such packets are only sent when there are no acknowledgment, control line and operation line message packets in the priority queue ( Thus, control line packets formed after half of the patch message has been transmitted are transmitted before the rest of the patch message). In the preferred embodiment, the reason for making the patch message relatively long is to identify its identification code as including several (up to 10) different individual / or groups of mobile station devices in the patch. is there. To process the patch message, counter M is set to zero (block 971), and then switch trunking card 454 calculates the number N of packets needed to store the patch message (block 973). . Next, first change the message's GETC code to 15
(Block 975), and then assign an encoded packet number to indicate the packet number of the patch message as well as a unique packet number used to distinguish the packet from other packets (block 977).
This causes the patch message to be "assembled."
The two BCH fields are calculated to protect the patch message from errors (block 979), and the completed packet is placed in a priority queue and the last patch message in this queue (this is the last working line message). Is stored later (block 981). After storing each patch packet in the priority queue, the queue counter is incremented (block 983), and the value of counter M is also changed to track the number of patch packets in the patch message (block 983). Block 985).
Control then loops back to block 975, where all packets within the patch message are checked (decision block).
Exit from this loop when formed (by the 987 test).

Switch trunking card 454 to remove the packet from the priority queue and send it to downlink trunking card 450 via land link 452
Are substantially the same as the steps performed by downlink trunking card 450 to transmit packets to the switching trunking card (see FIG. 12). Similarly, the process of block 630 in FIG. 9 performed by downlink trunking card 450 to receive packets transmitted from switch trunking card 454 via link 452 comprises the steps of downlink trunking. Steps performed by the exchange trunking card to receive packets sent from the ranking card (No. 13
(See figure).

FIG. 18 is a flowchart of an example control process performed by downlink trunking card 450 to process a message received from switch trunking card 454 (see block 632 of FIG. 9). . The downlink trunking card 450 first determines from the GETC code of the received message what type of message was received (blocks 1002-1010). If an acknowledgment message has been received (from the test of block 1002), block 632 directs block 612 to send a confirmation message (block 1012). If a control message has been received (from the test of block 1004), the checksum information is calculated (block 1014), the frame symbol is prepended to the message (block 1016), and the message is sent from the downlink to the point controller. Into the FIFO buffer (see block 606 of FIG. 9) (block 1018).
Blocks 1014 through 1018 are also performed (by the test of block 1008) on the received operating line message (by the test of block 1006). If a multi-packet patch message is received, the downlink trunking card 450 will send the entire patch message before any portion of the message is transmitted over the link 422 to the point controller 410. Test whether you have received First get the whole patch message (block
1022) Then execute blocks 1014 through 1018 to calculate the checksum, prefix the frame symbols, and store the entire patch message in a FIFO buffer. Operating lines, control lines, approval and management messages are
Note that it may arrive when only a part of the message is received. For this reason, the routine 632 keeps track of patch messages received halfway while processing other types of packets.

If a management message (eg, a test message or status message) arrives (due to the test of decision block 1010), routine 632 simply stores this message in a buffer for communication to point controller 410.

The logic routine performed by the downlink trunking card 450 to transmit the message from the buffer and point controller 410 in block 606 of FIG. 9 is simple, and the switch trunking card 454 is connected via link 456. Is exactly the same as the routine executed to transmit a message to the console 102 (see FIG. 15).

A method and architecture for communicating digital messages between the communication originating console 102 and the RF relay point controller has been described. This method and architecture allows messages to be efficiently transmitted over land-based communication links that have lower data rates than other higher-speed transmission paths in the downlink without significant degradation in overall transmission rates. Can be transmitted well. Conversion between protocols and message prioritization are achieved without significantly degrading the overall transmission rate, so that the downlink delay, and not the downlink transmission rate, is limited by point control. The processing speed of the vessel.

8.0 General description of message definitions and format Each of the links 420, 452, 456 that make up downlink 103
The following describes the messages and associated formats that are present in.

First, the link 412 (DL) between the point controller 410 and the downlink trunking cards 400-408,450
The messages and associated formats that exist above are described.

Thereafter, the messages and associated formats present on the land link 452 between the downlink trunking card 450 and the switch trunking card 454 will be described.

Finally, link 456 between exchange TC 454 and exchange 457
Describes the messages present and related formats.

The description of the message present on the link is divided into the description of the management message and the description of the global message. Global messages are described in the order of the device that sends the message. For example, a global message originating from the point controller 410 and existing on a particular link will be described, and then a global message transmitted by the exchange 457 will be described.

9.0 Point controller 410 and trunking cards 400 to 408,4
The messages on the high-speed data link 412 between the point controller 410 and the trunking card are two of the messages originating from the point controller and the messages originating from the trunking card. They can be classified into types.

9.1 Link between point controller 410 and trunking card
Types of messages communicated via 412 Point controller 410 and RF line trunking card 400 through
For messages communicated between 408, the point controller 410 sends a "global message" to the DLTC 450,
We do not use the term "global message" for such messages, since these messages are not "sent" to switch 457 in the sense that C will then send them to exchanges TC 454 and 457. However, in another sense, the point controller 410 and the RF trunking cards 400 to 40
All messages transmitted between 8 and requesting or confirming the allocation of scheme resources can be referred to as "global messages".

As mentioned previously, most global messages carried over downlink 403 correspond to messages carried over link 412 between point controller 410 and RF trunking cards 400-408. . For example, when the point controller 410 sends a working line assignment message to the working line trunking cards 402-408, the point controller also sends a global working line assignment message over the downlink 103 so that the working line is The console 102 is notified of the assignment, and the switch 457 defines the audio path necessary to connect the control shelf CS of the assigned operation line to the console (and possibly also to a dial telephone line).

Next, the messages communicated between the point controller 410 and the trunking card via the link 412 will be described in detail.

In the point controller of the embodiment of the present invention, DLTC 450 and RF
To communicate with line trunking cards 400-408,
Since the same messages and message formats are used, what follows is fully applicable to the communication between the point controller and the DLTC 450 over link 412 (DL).

In the preferred embodiment, the point controller 410 and the trunking station
The messages communicated between the cards 400-408,450 are shown in the table below.

9.2 "Management" messages on link 412 originating from point controller 410 Point controller 410 sends commands and polling requests to the trunking card to perform overall management of scheme 100. The types of management messages transmitted from the point controller 410 to the trunking card include resynchronization symbols, configuration commands, polling commands, downlink communication and test functions.

Next, a management message transmitted from the point controller 410 to the trunking card via the link 412 (DL) will be described.

9.2.1GETC setting command (hexadecimal 01) Destination: Trunking card Source: Point controller 410 The trunking card uses this message to
At power up or reset, it is configured as a control line, operating line or downlink trunking card.

One data byte of the message is used for configuration or reconfiguration of the trunking card.

The definitions of the bits in the data byte of the message are shown below.

b7b6-00 Disable GETC from processing any functional line.

01 Enable GETC for control line processing.

11 Enable GETC for downlink line processing.

 b5-0 Direct GETC to master point controller.

 1 Direct GETC to the support point controller.

b4b3b2b1b0 GETC line number at the pst point.

9.2.2 GETC broadcast count (hexadecimal 02) Destination: Trunking card Source: Point controller 410 The point controller 410 sends the current broadcast count number to the trunking card. The trunking card uses this to determine whether it has missed a line assignment or update message. If you missed it,
The trunking card sends back to the point controller 410 the number of the most recent broadcast count indicating the missed assignment.

The data bytes of the message include:

b7b6b5b4b3b2b1b0 ... broadcast count, module 256 On power up or reset, the trunking card will send a point controller 410 before reporting any missed assignments.
Wait for broadcast message count from.

9.2.3 GETC Status Request (hexadecimal 07) Destination: Trunking Card Source: Point Controller 410 Point controller 410 requests the state of the trunking card to monitor its activity. The monitored items include the current status of the trunking card (as determined by the internal status table), settings or format, the broadcast count of the trunking card, and the current activity of the trunking card (eg, )including.

The data byte of the message is
Contains the value of sending back to 0.

b7b6b5b4b3b2 = 000000 1b0 = 00 Current status 01 Setting request 10 Broadcast count 11 Activity request 9.2.4 GETC failsoft mode (hexadecimal F8) Destination: Trunking card Source: Point controller 410 The point controller 410 The trunking card is instructed to shift to the fail-soft operation mode in response to the communication.

The data bytes of the message are encoded as follows.

b7b6b5b4b3b2b1b0 = 01010101 (hexadecimal 55) 9.2.5GETC test message (hexadecimal FB) Destination: Trunking card Source: Point controller 410 The point controller 410 sets the trunking card to the test operation mode. Before the point controller 410 sends this command, the trunking card is put into a non-operational state through a setting command. The tests performed are modem checks,
Includes serial testing of point controller 410 and checking of hardware port values. In the modem test for DLTC 450,
Successive data byte values are transmitted over the downlink path. In a modem test on an RF trunking card, successive data bytes are transmitted over the air. In the serial test of the point controller 410, successive bytes are sent to the point controller 410 via the RS-232C bus.
In the hardware port test, the specified message of byte 2 is loaded into the specified port of the trunking card.

 The two bytes of the message are encoded as follows.

Byte 1 b7b6b5b4 Hardware port location b3 = 0 No hardware port test 1 Hardware port test enabled b2 = 0 No point controller 410 1 Serial test enabled b1 = 0 No modem test enabled 1 Modem test enabled b0 = 0 No RF modem test 1 RF modem test capability Byte 2 2 of 8 bits used for specified test
Hex Data 9.2.6 GETC Reset Message (Hexadecimal FD) Destination: Trunking Card Source: Point Controller 410 The Point Controller 410 commands the trunking card to reset.

The message data bytes are encoded as follows:

b7b6b5 = 000 b4b3b2b1b0 = trunking card identification code (eg line number) 9.3 Last message retransmission (hex FE) Point controller instructs trunking card to resend last message . This is done in the event of bit errors and message frame errors.

The message data bytes are encoded as follows.

b7b6b5 = 000 b4b3b2b1b0... line number (identification code) of GETC In the downlink 103, a management type message of the point controller 410 is generally sent from the point controller 410 to the downlink trunking card 450, and the downlink It is sent from the trunking card to the exchange trunking card 454. The acknowledgment message is used only between the downlink trunking card 450 and the switch trunking card 454 via the 9.2 kbp link 456.

9.4 Management messages sent from the trunking card to link controller 410 over link 412
Each "management" sent from the card to the point controller 410
The shape message will be described in detail below.

9.4.1 GETC setting response (hexadecimal 01) Source: Point controller 410 Destination: Trunking card The trunking card responds to the status request command transmitted from the point controller 450 to the point controller 410. The setting or format back to.

 The message data bytes are encoded as follows.

Byte 1 b7b6 = 00 Trunking card disabled from any functional line processing (abnormal) 01 Trunking card performing control line function 10 Trunking card performing control line function 11 Trunking card performing downlink function b5 = 0 GETC directed to master point controller 1 GETC directed to support point controller b4b3b2b1b0 Trunking card read from 5-bit DIP switch setting Identification numbers b7 and b6 are the same as those determined by the GETC setting command from the point controller.

b5, once directed by the alternate point controller,
The GETC may not be the same, even if there is active communication, because it may not be found. in this case,
Turn to an active point controller.

Byte 2 Lower 8 bits forming 14-bit FCC frequency code. These bits are read from the GETC DIP switch.

Byte 3 Upper 6 bits forming 14-bit FCC frequency code (embedded in lower bits of message # 3). These bits are read from the GETC DIP switch.

9.4.2 GETC Broadcast Count (hexadecimal 02) Destination: Point controller 410 Source: Trunking card The trunking card sends its current broadcast count to the point controller.

This message is a point controller that asks for the broadcast count.
Sent in response to a status request from 410 or when the next broadcast count message generated by point controller 410 does not match the broadcast count on the trunking card.

At power up or reset, the trunking card waits for a broadcast count message from the point controller 410 and sets its broadcast count to that value.

The message data byte has a radix 256 broadcast count.

9.4.3 GETC status response (hexadecimal 07) Destination: Point controller 4
10 Source: Trunking card The trunking card sends back its current activity response requested by the point controller 410 in a status request message to the point controller 410.

Current activities include the RF carrier, including the broadcast indication, the initial power up or reset state, and the type of communication in progress.

 The message data byte contains the following bits:

b7 = 0 Polling after reset 1 First poll after reset b6 = 0 RAM area OK 1 RAM area error b5 = 0 No transmission in progress 1 Transmission in progress b4 = 0 No carrier received 1 Carrier received Medium b3 = 0 No emergency situation 1 Emergency call b2 = 0 Standard call 1 Special call b1, b0-00 Voice communication 01 DVG communication 10 Data communication 11 Interconnect communication 9.4.4 Current state of GETC (hexadecimal F9) Destination: Point controller 410 Source: Trunking card When a trunking card is requested, it sends back the current state to the point controller 410. The current state is trunking
Indicates the current activity of the card. The message byte is encoded to be the current state of the trunking card (0-255).

9.4.5 GETC test message (hexadecimal FB) Destination: Point controller 410 Source: Trunking card The trunking card responds to the point controller 410,
Inform hardware port test type. This message is sent periodically in the operation of the trunking card test mode. The trunking card reports the state of the outgoing input latch or buffer. Report a total of eight hardware registers.

The two message bytes are encoded as follows.

Byte 1 b7b6b5b4b3 = 00000 b2b1b0 Hardware port number Byte 2 8-bit value in the hardware port specified in byte # 1.

9.4.6 Retransmit Last Message (Hex FE) The trunking card instructs the point controller 410 to retransmit the last message. This is done in the event of bit errors and message frame errors. The message data bytes are encoded as follows.

b7b6b5 = 000 b4b3b2b1b0 Line number 9.5 Global message of link 412 originating from point controller 410 Next, some global messages from the point controller to the trunking card will be described in detail.

9.5.1 Outgoing Control Line Single Slot Message (Hex OD) Destination: Trunking Card Source: Point Controller 410 The Point Controller sends a single slot message to control line GETC. This message includes line update, dynamic group reorganization, aliasing ID, status confirmation, time mark, device key connection / key release / enable / disable, point ID and mode of operation.

The message data bytes are encoded as follows.

Byte 1 b3b2b1b0 = 0000 Lowest nibble of radio message in upper nibble Byte 2 Next byte of radio message Byte 3 Next byte of radio message Byte 4 Most significant byte of radio message 9.5.2 Assignment of outgoing control line ( Hexadecimal 08) Destination: Trunking card Source: Point controller 410 The point controller 410 sends a line assignment to the trunking card. The outgoing control line assignment consists of a 28-bit radio information field, a 4-bit field indicating the originator of the assignment, an 8-bit working line setting and a 1/2 logical ID and hang time. The point controller 410 can also dynamically reconfigure the type of working line for different communication modes (voice, DVG, data or interconnect).

The message data bytes are encoded as follows.

Byte 1 b3 = 0 Call originated by radio 1 Call originated from console 102 b2b1b0 = 000 Lowest nibble of radio message in upper nibble Byte 2 Next byte of radio message Byte 3 Next byte of radio message Byte 4 Most significant byte of radio message Byte 5 Hang time byte b7b6b5b4b3b2b1b0 = 0 to 255 seconds Byte 6 Working line setting byte and 1/2 logical ID b7 = 0 Standard handshake of working line 1 Hand of working line for special call Shake b6 = 0 No repetition of inward operation line message 1 Repetition of inward operation line message b5b4b3b2b1b0 1/2 logical ID of second message in two-slot outward message 9.5.3 Overseas operation line wireless programming message (Hexadecimal 19) Destination: Trunking card Source: Point controller 410 Point controller 410 is working line On the trunking card,
Instructs the mobile station's wireless device to buffer data to be sent.

The length of the message data byte is variable,
It is encoded as follows.

9.5.4 Outgoing control line connection message (hexadecimal OB) Point controller 410 sends a connection message to the trunking card. The concatenation message is a two-slot message to the mobile station's wireless device. Point controller 41
0 informs the mobile station of status information, preliminary planning of dynamic group reorganization, assignment of IDs, and assignment of programming lines.

The point controller sends 8 message bytes of information to the trunking card. These message data bytes are encoded as follows.

Byte 1 b3b2b1b0 = 0000 Lowest nibble of the radio message in the upper nibble of the first radio slot Byte 2 Next byte of the first radio slot of the radio message Byte 3 Next byte of the first radio slot of the radio message Byte 4 Most significant byte of first radio slot of radio message Byte 5 b3b2b1b0 = 0000 Lowest nibble of second radio slot of radio message in upper nibble Byte 6 Next byte of second radio slot of radio message Byte 7 Next byte of the second radio slot of the radio message Byte 8 Most significant byte of the second radio slot of the radio message 9.5.5 Audio repetition enable / disable (hexadecimal 1A) point control for outgoing lines 410 enable or disable mobile communication trunking card for mobile audio repetition path To command as. This is used to quickly deactivate an inactive user.

The message data bytes are encoded as follows.

b7 = 0 Disables the audio repeat path 1 Enables the audio repeat path b6b5 = 00 b4b3b2b1b0 Number of the specified line of GETC 9.5.6 Outgoing operation line drop message (hexadecimal 1)
C) The point controller 410 instructs the working line to immediately end all communication activities. The message data bytes are encoded as follows.

b7b6b5 = 000 b4b3b2b1b0 GETC (working line) number 9.5.7 Identification code of transmitting FCC station (hexadecimal F7) Command to send via The FCC ID is 12 bytes using 00 bytes.
Adjusted to byte length. The format of the message data byte is as follows:

9.6 Global Message Sent from Trunking Card 450 to Point Controller 410 over Link 412 Next, the format of each "global" message sent from the trunking card to point controller 410 over link 412 Will be described in detail.

9.6.1 Incoming Control Line Message (Hex 08) Destination: Point Controller 410 Source: Trunking Card The trunking card sends a radio control line message to the point controller 410. The inbound control line message is composed of actual 28-bit wireless data and a 4-bit header. The 4-bit header consists of zeros. The trunking card sends 4 bytes of information to the point controller. The message data bytes are encoded as follows.

Byte 1 b3b2b1b0 = 0000 Lowest nibble of message in upper nibble Byte 2 Next byte of radio message Byte 3 Next byte of radio message Byte 4 Most significant byte of radio message 9.6.2 Inward working line message (hexadecimal) 10) Destination: Point controller 410 Source: Trunking card The trunking card sends a standard inward working line message to the point controller 410 without the mobile station's AVL information. Messages sent to point controller 410 include key connect, key release, line drop, zero message and wireless dot message.

The trunking card sends three bytes of message information to the point controller 410. These bytes are encoded as follows.

Byte 1 b3b2b1 = 000 b0 = 0 Normal message or line drop
To complete the standard initial handshake of the radio message in the lowest nibble or upper nibble of the message 1 dot, a line drop occurred without the radio arriving on the specified working line.

Byte 2 Next byte of radio message Byte 3 Most significant byte of radio message 10.0 Message on land link 452 between downlink trunking card 450 and exchange trunking card 454 Interface between DLTC 450 and exchange TC 454 Is a standard land series link 452, each end of which is terminated with standard wiring and a standard connector. Audio wiring at all points enters the dispatch center via standard telephone blocks. Telephone line is DLTC 450 and exchange TC 454
(Each line has its own cable). Use standard connectors on each end of the telephone cable.
Link 452 operates in full duplex mode, with message transmission in both directions at any given time. Exclusive or BCH checksums are used to ensure data integrity.

The transmission bit rate of the land link 452 is
9.6kb as determined by trunking card 450
p. The messages are transmitted in packets in link 452, with each packet having one or two messages. Data is exchanged in a packet over link 412 using automatic retransmission, if not an acknowledgment protocol. That is, the transmitting trunking card retransmits the data packet (up to three times in the preferred embodiment) until the receiving trunking card sends an acknowledgment message indicating that the packet was correctly received.

The receiving trunking card can acknowledge the correct reception of the packet by sending an acknowledgment message to the transmitting trunking card. This acknowledgment message specifies the message type and packet number. If the received packet contains a management message that requires a response of the receiving trunking card, acknowledgment is performed by sending the requested response. If no acknowledgment is received within 3 message times since the last byte of the packet was sent, the packet will be sent (up to 3 times)
Resubmitted automatically.

Packet frames can be transmitted without interruption, and acknowledgment messages are scattered among other packets when they occur. Link 452 is synchronous so that if the transmit buffer is empty, a dot is transmitted.

The frame format of the data packet transmitted over link 452 is as follows.

10.1 Management messages transmitted over land link 452 between DLTC 450 and switch TC 454 To transmit global messages between DLTC 450 and switch TC 454, maintain byte and message synchronization, and send management state information: Management messages are used. The link is used in full-duplex mode, and message transmission occurs in both directions at any given time. Use exclusive-or checksums to guarantee data integrity. An "acknowledge" or other form of management message forces message and byte synchronization. The DLTC responds by sending a type message to the downlink, working or control line management message.

Next, a land link 452 between DLTC 450 and switch TC 454
An example of a format of a management message transmitted through the communication device will be described.

10.1.1 Operating Line Format Message Message Type Management Message Number 87 Total Length 6 Bytes Sent Sent by DLTC 450 only in response to receiving the operating line command from point controller 410.

Source DLTC 450 Original source Point controller 410 Destination switch 457 Final destination Switch 457 10.1.2 Downlink line type message Message type management Message number 88 Total length 6 bytes When sending Sent only by DLTC450 in response to receiving a downlink line command from the point controller.

Source DLTC 450 Original source Point controller 410 Destination switch 457 Final destination Switch 457 10.1.3 Control line format message Message type management Message number 89 Total length 6 bytes When sending Sent only by DLTC 450 in response to receiving the operation line command from point controller 410.

Source DLTC 450 Original source Point controller 410 Destination switch 457 Final destination Switch 457 10.1.4 Acknowledgment Message Message Type Management Message Number 90 Total Length 6 Bytes Sent Sent by DLTC 450 or switch 457 in response to receiving a global message correctly.

Source Switch 457 or DLTC 450 Source Source Switch 457 or DLTC 450 To DLTC 450 or Switch 457 Final Destination DLTC 450 or Switch 457 10.1.5 Unacknowledged Message Message Type Management Message Number 91 Total Length 6 Bytes Sent In response to an incorrectly received Global Message, sent by either.

Source Switch 457 or DLTC 450 Source Source Switch 457 or DLTC 450 To DLTC 450 or Switch 457 10.2 Global message originating from point controller 410 communicated from DLTC 450 to switch TC 454 via land link 452 1 when land link 452 passes through downlink 103 between point controller 420 and switch 457 One branch carries global message messages between the DLTC 450 and the switch TC 454. There are two types of such global messages: switch 457
, A console request issued to the point controller 410, and a command from the point controller. The point controller command may be a response to a console resource request or a response to a mobile station resource request. DLTC 4
50 and switch TC 454, in the preferred embodiment, do not directly recognize the contents of the global message they are transmitting.

The main processor of the switch can request the point controller to provide an RF line in response to a console 102 push-to-talk (PTT) command. Switch 457 sends the unacknowledged message format BK1 Barker Byte 57 BK2 Barker Byte 12 GID Message ID = 91 PKT PKT packet number of this message PKT Packet number of recognized global message CHK Exclusive OR check sum 10.2 DLTC 450 Global message originating from the point controller 410 communicated via the land link 452 to the switch TC 454 from the terrestrial link 452 when the land link 452 passes through the downlink 103 between the point controller 420 and the switch 457. Convey global message messages between DLTC 450 and switch TC 454. There are two types of such global messages: switch 457
, A console request issued to the point controller 410, and a command from the point controller. The point controller command may be a response to a console resource request or a response to a mobile station resource request. DLTC 4
50 and switch TC 454, in the preferred embodiment, do not directly recognize the contents of the global message they are transmitting.

The main processor of the switch can request the point controller to provide an RF line in response to a console 102 push-to-talk (PTT) command. Switch 457 can also request that the RF line be released after the console key release command. In a patch or "simultaneous selection" operation,
Before making an RF line request, a patch ID from the point controller is required. To deactivate a patch or "simultaneous selection", the patch ID must also be deactivated.

All links are allocated and deallocated via the point controller 410 since the point controller manages the RF lines during normal operation of the scheme. Respond to all mobile, portable and console line requests. Assignment or deallocation of any line causes a message to be sent to the originating center via the downlink. Point controller 410
Also assigns a patch ID for the patch and simultaneous selection operations. Such deassignment of patch IDs also generates a message to the originating center via the downlink.

Next, an example of a repertoire of global messages transmitted from DLTC 450 to switch TC 454 via land link 452 in response to a global message received by DLTC from point controller 410 will be described.

10.2.1 Single-slot control line message Message type Global message number 13 Total length 14 bytes When sending Control information is requested from the sending center or, when requested, sent from the point controller to the sending center.

Source DLTC 450 Original Source Point Controller 410 Destination Switch TC 454 Final Destination Console 102 or other control section of Switch TC 457 10.2.2 2-slot control line message Message type Global message number 8 Total length 10 bytes When sending When the arbitrary line assignment is issued, it is issued by the point controller. This includes standard and emergency line assignments.

Source DLTC 450 Original Source Point Controller 410 Destination Switch TC 454 Final Destination Console 102 or other control section of Switch TC 457 10.2.3 Operation line message Message type Global message number 16 Total length 16 bytes When sending An operation line message is issued by the point controller. This includes all operating line messages.

Source DLTC 450 Original Source Point Controller 410 Destination Switch TC 454 Final Destination Console 102 or other control section of switch 457 10.2.4 Patch / Simultaneous Selection Set Confirmation Message Message Type Global Message Number 82/85 Total Length 8 Bytes When Sending DLTC 450 Receives Modem GID of 82 (Patch Set Approval) or 85 (Simultaneous Selection Set Approval) Sometimes sent. Both modem messages are converted to a single console message. The protocol conversion is the same for both GIDs.

Source DLTC 450 Original Source Point Controller 410 Destination Switch TC 454 Final Destination Console 102 or other control section of switch 457 10.2.5 Patch / Simultaneous selection activation / deactivation message Message type Global message number 80/83 Total length 8 bytes When sending Sent when a similar message is received from DLTC 450 from point controller 410. These messages result in messages to the console 102 of the shipping center. GETC at shipping center is patching /
An inactive message GID 80 or a simultaneous select active / inactive message GID is received, which results in a console message. Patch / simultaneous selection operation (MID 16) and patch /
Simultaneous selection inactive (MID 11) Source DLTC 450 Original source Point controller 410 Destination exchange TC 454 Final destination Console 102 or other control section of exchange 457 10.3 Global message originating from the console, transmitted from the exchange TC 454 to the BLTC 450 via the land link 452.
Global messages can be generated that are propagated to zero. The global message generated by the exchange in this way
In the preferred embodiment, it is derived from commands issued by the console 102 operator. When switch TC 454 receives a global message from switch 457, switch TC simply sends the message (after translation and other modifications) to DLTC 450 via land link 452. DLTC 450 sends this message to point controller 410 for processing.

In the preferred embodiment, all global messages initiated from the console (switch) are either "resource request" or "status" messages. Console PTT
When a button is pressed and an RF line is requested, a group or individual call message is sent to the point controller via the downlink 103. Both messages are a resource request (RF
(Line request) message.

As an example of a common scenario, an RF line is allocated,
Assume that a conversation has begun between the console operator and the mobile transceiver of the mobile station. When the console operator "unkeys" the microphone, a global key release message sent from the console (exchange)
Sent to point controller in response to console key release. The global key release message is transmitted from switch 457 to point controller 410 via downlink 103 and processed by the point controller.

The console key release command may or may not cause the point controller 410 to deallocate the line. If the scheme is configured for relaying transmissions, the deallocation of the line (by the point controller) immediately follows any key release. However, if the method is message relay, a hold (“hang”) time is set so that the line does not drop immediately after the key is released. If the line is open and available, a key message is sufficient to inform the point controller of the console 102's willingness to use the line.

As another example, in the case of a multiple group operation, a patch ID is assigned to each patch and the simultaneous selection button of the console 102. If a patch ID is generated or modified on console 102, a global "patch change" issued from the console
A message is sent from switch 457 to point controller 410 via downlink 103. The information of the patch ID and the group and the individual set included in the “patch change” message is stored in the point controller. Multiple groups of calls are activated and deactivated through messages to the point controller. These messages are requests to use the patch ID. The point controller must check the format of the scheme before approving the use of the patch ID.

Next, the types of console-initiated messages transmitted from the exchange TC 454 to the DLTC 450 via the land link 452 are described in detail. Each of these land messages corresponds, of course, to a console-initiated global message carried by link 456 between switch 457 and switch TC454.

10.3.1 Single-slot control line message Message type Global message number 08 Total length 14 bytes Send When Sent when switch 457 receives a global message with a message ID of 24, 25, 30, 31, or 34.

Source Switch TC 454 Original Origin Other Control Clause of Console 102 or Switch 457 Destination DLTC 450 Final Destination Point Controller 410 Control Line Inward MT-A 00 10.3.2 Operating line message Message type Global message number 16 Total length 12 bytes When sending Sent when switch 457 receives a global message with a message ID of 27, 28 or 33.

Source Switch TC 454 Original Source Console 102 or other control section of switch 457 Destination DLTC 450 Final Destination Point Controller 410 10.3.3 Collective Message of Patch / Simultaneous Selection Message Type Global Message Number 81/84 Total Length 12 Bytes Sent When switch 457 receives 29 console message IDs. The received message is split into one of two sets of messages, depending on whether the message is a patch or a simultaneous selection message. Modem GID for simultaneous select message is 8
4 and 85, and the GIDs for the patch message are 81 and 82. Two GIDs are required. One GID is used as a header message that carries the group count and individual count associated with the set. The other GID is used to convey groups and individuals in the set.

Source Switch TC 454 Original Origin Console 102 Destination DLTC 450 Final Destination Point Controller 410 10.3.4 Patch / Simultaneous activation / deactivation message Message type Global message number 80/83 Total length 8 bytes When sending The exchange 457 sends a 27 (patch / simultaneous activation) or 28 (patch / simultaneous activation) message Sent when a global message with an ID is received.
Depending on the conditions of the point controller 410, these messages
(Patch enabled / disabled) or 83 (simultaneous selection enabled / disabled). The format of both messages is the same.

Source Switch TC 454 Original Source Console 102 or other control clause of Switch 457 Destination DLTC 450 Final Destination Point Controller 410 11.0 Message on link 456 between switch 457 and switch TC 454 Both global and regional messages are transmitted at high speed between switch trunking card 454 and switch 457.
Transmitted via 456. Next, messages transmitted via the link 456 will be described.

11.1 Management Messages Conveyed Between Switch 457 and Switch Trunking Card 454 over Link 456 The individual management messages conveyed between switch TC 454 and switch 457 in the preferred embodiment will now be described in detail.

11.1.1 Operating Line Format Message Message Type Management Message Number 01 Total Length 3 Bytes Sent In response to receiving a transmission format message from switch 457, sent only by switch TC 454.

Source Switch TC 454 Original Source Switch TC 454 Destination Switch 457 Final Destination Switch 457 11.1.2 Downlink Line Format Message Message Type Management Message Number 02 Total Length 3 Bytes Sent In response to receiving a transmit format message from switch 457, only sent by switch TC 454.

Source Switch TC 454 Overall Source Switch TC 454 to Switch 457 Final Destination Switch 457 11.1.3 Control line type message Message type management Message number 03 Total length 3 bytes When sending Only the switch TC 454 sends in response to receiving a send type message from the switch.

Source Switch TC 454 Original Source Switch TC 454 Destination Switch 457 Final Destination Switch 457 11.1.4 Confirmation Message Message Type Management Message Number 04 Total Length 3 Bytes Sent After receiving a global message with the correct checksum, switch TC 454 or switch 457 sends it.

Source Switch 457 or Switch TC 454 Original Source Switch 457 or Switch TC 454 Destination Switch TC 454 or Switch 457 Final Destination Switch TC 454 or Switch 457 11.1.5 Unacknowledged ("deny") message Message type management Message number 05 Total length 3 bytes When sending After receiving a global message with the correct checksum, switch TC 454 or switch 457 sends it. Receipt of this message requires that the last message be resent.

Source Switch 457 or Switch TC 454 Original Source Switch 457 or Switch TC 454 Destination Switch TC 454 or Switch 457 Final Destination Switch TC 454 or Switch 457 11.1.6 Transmission format message Message type management Message number 06 Total length 3 bytes When sending To set the format of the exchange TC 454,
Sent from switch 457 at a rate of 5 seconds to maintain byte and message synchronization.

Source Switch 457 Original Source Switch 457 Destination Switch TC Final Destination Switch TC 11.2 Global message on link 456 originating from exchange 457 (console 102) and transmitted from exchange to exchange TC 454 Next originating from exchange 457, link 45 from exchange 457
Examples and definitions of the format of global messages sent to switch trunking card 454 via 6 are described.

11.2.1 Group call messages Message type Global, control line Message number 24 Total length 9 bytes GETC code 08 When sent Sent by console 102 to request an RF line to a group of field devices (mobile or portable) . This message is RF
Generated by any console's PTT key for a group, whether or not a line assignment already exists.

Source Switch 457 Original Source Console 102 or other control section of Switch 457 Destination Switch TC 454 Final Destination Point Controller 410 Control Line Inward MT-A 00 11.2.2 Individual call messages Message type Global, control line Message number 25 GETC code 08 Total length 9 bytes When sending console 102 to request RF line for individual field device (mobile or portable)
Sent by This message is generated by the console's PTT key for an individual destination, whether or not an RF line already exists.

Source Switch 457 Original source Console 102 Destination DLTC 450 Control line inward MT-A 10 Final destination point controller 410 11.2.3 Key release message Message type Global, operating line Message number 26 GETC code 10 Total length 8 bytes When sending Sent by console 102 to notify point controller 410 of console key release (this message was assigned The line may or may not be dropped).

Source Switch 457 Original Source Console 102 Destination DLTC 450 Final Destination Point Controller Working Line Inward MT-A 0011 11.2.4 Patch operation ID request message Message type Global, operation line Message number 27 GETC code 10 Total length 8 bytes When sending When setting patch or simultaneous selection,
Sent by console 102. This message requests that the patch ID be activated, that mobile stations and individual stations be notified that the patch ID has been activated, and that the console 102 be allowed to activate the patch ID. The patch ID has already been defined to the point controller 410 by another message.

Source Switch 457 Original source Console 102 Destination DLTC 450 Final destination Point controller 410 Working line inward MT-A 1110 11.2.5 Patch ID non-operation request message Message type Global, operation line Message number 28 GETC code 10 Total length 8 bytes When sending Patch or simultaneous selection from front panel (when disabled) or when patch or simultaneous selection Sent by console 102 when clearing memory contents.

Source Switch 457 Original source Console 102 Destination DLTC 450 Final destination Point controller 410 Working line inward MT-A 1111 11.2.6 Patch ID change assignment message Message type Global, patch Message number 29 GETC code 15 Total length Minimum 8 bytes, maximum 40 bytes Sending Sent from the console 102 when changing or clearing the patch or simultaneous selection memory. This message is used to inform the point controller 410 which groups and individual stations are associated with the patch ID. 0 to 16
(Group or individual) can be grouped in any combination (group or individual). The last item is the patch ID of the group
It is.

Source switch 457 Original source Console 102 or other control section of switch 457 Destination DLTC 450 Final destination point controller 410 11.2.7 Emergency Alert Message Message Type Global, Control Line Message Number 30 Total Length 9 Bytes Sent Used by console 102 to declare an emergency to a group. This message is used to inform the point controller 410 which group to place in an emergency. The specified group of communications takes place at the highest priority available in this manner.

Source Switch 457 Original source Console 102 Destination DLTC 450 Final destination Point controller 410 Control line inward MT-A 01 11.2.8 Emergency line request message Message type Global, control line Message number 31 Total length 9 bytes When sending Used by the console 102 to request a line from the point controller 410 for voice transmission. This message is used when the dispatcher is pressed by the PTT and the group they are trying to communicate with is in an ongoing emergency.

Source Switch 457 Original source Console 102 Destination DLTC 450 Final destination Point controller 410 Control line inward MT-A 01 11.2.9 Status Page Message Message Type Global, Control Line Message Number 32 Total Length 9 Bytes Sent Used by console 102 to query the current status of the device. The field radio is queried by the point controller 410 and the status of the device is entered in a status message to the console 102.

Source Switch 457 Original source Console 102 Destination DLTC 450 Final destination Point controller 410 Control line inward MT-A 11 MT-B 111 MT-C 001 11.2.10 AP reset message Message type Global, message number 33 Total length 9 bytes When sending Used by switch 457 to inform point controller 410 that the main processor has just exited the reset state. Point controller 410 must clear all temporary buffers and power up its database.

Source Switch 457 Original Source Console 102 Destination DLTC 450 Final Destination Point Controller 410 11.2.11 Emergency Cancellation Message Message Type Global, Control Line Message Number 34 Total Length 9 Bytes To Send In order to instruct the point to cancel an ongoing emergency, connect the point to console 102 (or to switch 457). Other control clauses). This message, apart from one bit change,
Same as the group call message.

Source Switch 457 Original Origin Console 102 or other control section of switch 457 Destination DLTC 450 Final destination Point controller 410 Control line inward MT-A 00 11.3 Global messages on link 456 originated by point controller 410 and sent from switch TC 454 to switch 457 Messages from the point controller are resources generated by either console 102 or field devices (mobile, portable). This is a response to the request. Point controller
Allocate and deallocate RF lines, manage patch IDs, and relay all key connections and key releases, regardless of source. In addition, for multiple group calls, a set of groups is represented using a patch ID. Control and assignment of patch IDs
This is performed by the point controller. For multiple group calls of mobile stations or consoles, the patch ID is set before the PTT and permission to use the patch ID is issued from the point controller.

In response to the global message originating at point controller 410 and received by switch TC 454 via link 452, the switch
The global message transmitted from the TC 454 to the exchange 457 via the link 456 will be described.

11.3.1 Line allocation message Message type Global, control line Message number 8 GETC code 08 Total length 10 bytes When sending PTT on site device or PTT on console
In response to any of the above, the point controller issues. This message is a response to a group call or individual call message.

Source DLTC 450 Original source Point controller 410 Destination exchange 457 Final destination Broadcast to the console 102 that issued the request or (in the case of a group of mobile stations) all consoles 102 Control line outbound MT-A 00 11.3.2 Device key connection message Message type Global, control line Message number 9 GETC code 0D Total length 9 bytes When sending PTT on site device or PTT on console
In response to any of the above, the point controller issues. This message is used when a line has been assigned but is inactive (ie, there is no ongoing conversation).

Source DLTC 450 Original source Point controller 410 Destination switch 457 Final destination Broadcast to all consoles 102 11.3.3 Key Release / Circuit Release Message Message Type Global Message Number 10 GETC Code 0D Total Length 9 Bytes Send When issued by the point controller in response to the release of the PTT by either the field device or console 102. It is. This message may be issued twice. Once, only the key release is notified to the exchange 457 (message relay), and once, the dropped line is notified to the system (transmission relay).

Source DLTC 450 Original source Point controller 410 Destination switch 457 Final destination Broadcast to all consoles 102 11.3.4 Patch ID inactive message Message type Global, control line Message number 11 GETC code 19 Total length 8 bytes When sending Sent by the point controller in response to the end of the multiplex group format. Emitted when the console 102 clears the selection of a patch or multiple group of simultaneous selections or when the mobile station clears a patch.

Source DLTC 450 Original Origin Point Controller 410 Destination Switch 457 Final Destination Console 102 11.3.5 Message for assigning group ID to patch ID Message type Global message number 12 GETC code 00 Total length 9 bytes Sent When the change of patch or simultaneous selection is approved, it is sent from the point controller. This message is used to inform console 102 which group is assigned to the patch ID. The assignment is issued one message at a time. When this message is received, the patch ID specified in the message is automatically activated.

Source DLTC 450 Original Origin Point Controller 410 Destination Switch 457 Final Destination Console 102 11.3.6 Individual ID assignment message for patch ID Message type Global, control line Message number 13 GETC code 0D Total length 9 bytes Sent When the change of patch or simultaneous selection is approved, sent from the point controller. This message is used to inform console 102 which individual has been assigned to the patch ID. This assignment is issued one message at a time. When this message is received, the patch ID specified in the message is automatically activated.

Source DLTC 450 Original Origin Point Controller 410 Destination Switch 457 Final Destination Console 102 11.3.7 Point ID message Message type Global, control line Message number 14 GETC code 0D Total length 9 bytes When sending Sends the console 102 the point status and fail software information. Also tell the location of the control line.

Source DLTC 450 Original source Point controller 410 Destination switch 457 Final destination Console 102 that made the request 11.3.8 Line update message Message type Global, control line Message number 15 GETC code 0D Total length 9 bytes When sending Sends from the point controller while the line is in use. The group or individual that uses the line is specified, and whether the line is performing digital transmission or analog transmission is notified.

Source DLTC 450 Original Origin Point Controller 410 Destination Switch 457 Final Destination Console 102 11.3.9 Patch ID activation message Message type Global message number 16 Total length 8 bytes When sending Sent from the point controller after the patch ID is activated. This message is used for both patching and simultaneous selection.

Source DLTC 450 Original Origin Point Controller 410 Destination Switch 457 Final Destination Console 102 11.3.10 Patch Set Acknowledgment Message Type of Message Global Message Number 17 Total Length 9 Bytes Sent After receiving the patch set change message, it is sent from the point controller. This message is used for both patch and simultaneous selection and is a global acknowledgment for the change message.

Source DLTC 450 Original Origin Point Controller 410 Destination Switch 457 Final Destination Console 102 11.3.11 Emergency Line Update Message Message Type Global Message Number 18 Total Length 8 Bytes To Send Once the wireless device declares an emergency, the point controller 410 sends this message to the originating center. The call center uses this information to
Display emergency information in 2.

Source DLTC 450 Original Origin Point Controller 410 Destination Switch 457 Final Destination Console 102 11.3.12 Emergency line assignment message Message type Global message number 19 Total length 10 bytes When sending This message is a response to the emergency line request message. When this message is received, the originating center creates an audio path to the appropriate console 102 and indicates the logical ID that sends this audio.

Source DLTC 450 Original Origin Point Controller 410 Destination Switch 457 Final Destination Console 102 11.3.13 Status message Message type Global message number 20 Total length 9 bytes When sending This message is relayed from the wireless device to the originating center via the point controller 410. This can be transmitted by the radio in response to a query or at the request of the radio operator.

Source DLTC 450 Original source Radio via point controller 410 Destination switch 457 Final destination Console / computer assisted dispatch system 11.3.14 Point controller 410 reset message Message type Global state message Message number 21 Total length 9 bytes When sending When point controller 410 comes out of reset state (for any reason), this message is sent to the originating center. To clear both sets of operational databases.

Source DLTC 450 Original Source Point Controller 410 Destination Switch 457 Final Destination Main Processor (Console) Although the present invention has been described in what is presently considered to be the most practical and preferred embodiments, the claims are not limited to the embodiments described herein but have the novel features and advantages of the present invention. It is to be understood that all modifications and equivalents are to be covered.

12.0 Appendix I Summary of Message Field Definitions The following summary of field definitions corresponds to the field names described above for previous message formats.

Continuation of the front page (31) Priority number 56924 (32) Priority date June 3, 1987 (33) Priority country United States (US) (31) Priority number 57046 (32) Priority date 1987 March 3 (33) Priority claim country United States (US) (31) Priority claim number 85490 (32) Priority date August 14, 1987 (33) Priority claim country United States (US) (31) Priority claim No. 85491 (32) Priority date August 14, 1987 (33) Priority country United States (US) (31) Priority claim number 85572 (32) Priority date August 14, 1987 (33) Priority country United States (US) (31) Priority number 85663 (32) Priority date August 14, 1987 (33) Priority country United States (US) (72) Inventor Hughes, Houston Howard, Third United States of America, 24502, Deborah River, Lynchburg, Virginia, No. 237 (72) Inventor Gordon, Robert Terrill United States, 24503 Lynchburg, Virginia, Downing Drive, No. 3233 (72) Inventor Hatti, David Leo United States, 24502, Virginia, Lynchburg, Robinson Drive, No. 204 (72) Inventor Eulman, Bruno United States, 24501 Bertelli Drive, Lynchburg, Virginia, No. 221 (56) References JP-A-57-171861 (JP, A) JP-B-46-36365 (JP, B1) US Patent 4,100,533 (US, A) U.S. Pat. No. 4,449,246 (US, A) U.S. Pat. No. 4,422,171 (US, A) U.S. Pat. No. 4,648,671 (US, A) U.S. Pat. No. 4,689,805 (US, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04B 7/24-7/26 H04Q 7/00-7/38 H04L 11/00

Claims (6)

(57) [Claims] 1. A digital trunk land mobile radio system, comprising: a plurality of land based digital trunk radio repeater transceivers in radio communication with a portable and / or mobile radio transceiver on a radio frequency channel. Wherein the trunk radio repeater transceivers are connected together by a common data link and communicate trunking control signals to each other via the common data link, the trunking control signals being transmitted by one of the portable and / or mobile radio transceivers. The terrestrial base repeater station, which controls the trunk radio repeater transceiver to temporarily allocate the radio frequencies used as needed, such as a communication switch or dispatch console with the previous repeater station. A serial communication downlink arrangement for coupling trunking control and other signals through a downlink between external sources, including a downlink processor, wherein the downlink processor is used to communicate the trunking control signal. Coupled to each of the trunk wireless repeater systems over the common data link, the downlink processor receiving a trunking control signal from the external source over the downlink, and receiving the trunk wireless repeater signal over the common data link. The serial communication downlink arrangement for communicating the trunking control signal with a transceiver. 2. The digital trunk land mobile radio system of claim 1, wherein said downlink processor receives individual first and second site messages from said repeater on said data link. The system comprising: means for packing the first and second messages into a single message; and means for transmitting the single message to the external source via a downlink. 3. The digital trunk land mobile radio system according to claim 1, wherein said downlink processor is means for receiving a single message from the downlink; And a means for unpacking to a second site message, and means for transmitting the unpacked message to the repeater over the data link. 4. The digital trunk land mobile radio system of claim 1, wherein said repeater transceiver is digitally communicated with said portable or mobile radio transceiver over a radio frequency channel using a synchronous serial communication protocol. Performing wireless communication of control signals, wherein said downlink processor communicates digital control signals on said downlink with said external source using the same synchronous serial communication protocol. 5. The digital trunk land mobile radio system of claim 1, wherein said downlink comprises a telephone line. 6. The digital trunk land mobile radio system according to claim 1, wherein said downlink processor is used for at least one protocol and said downlink when not used for said data link. Said system comprising a protocol converter for converting between at least one protocol.