JPS62271589A - Terminal line setting control system for time division multiplex communication system - Google Patents

Abstract

PURPOSE:To improve the efficiency of using a channel B by exchanging a control signal with the aid of a time slot for the control signal after a master equipment allocates the numbers of the time slots for control signals. CONSTITUTION:In initialization the master equipment 10 allocates inherent time slots to terminals such as telephone sets 20, 30, 40 and 50. In an online state, the telephone sets occupy the given time slots and transmit signals. If a multiframe is used as a transmission frame, plural channels individually allocated to the telephone sets as channels D (control channels) and one channel shard with all the telephone sets are prepared. By exchaning a control signal through the channels D, channels B(for sound or data) can be allocated to the telephone sets as necessary. In such a way, the comparatively small number of channels B can be shared with a plenty of telephone sets, whereby the efficiency of using the channels B can be improved.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Industrial Application Field] The present invention connects a main device and a plurality of terminals to a transmission line, and transmits a time-sharing system on this transmission line. The present invention relates to a time division multiplex communication system that provides a plurality of signal transfer channels for communication, and particularly to a terminal (telephone) line setting control method for a key telephone system.

[Conventional technology]

In recent years, in communication systems such as button telephones, signal transmission between a main device with a switching function and the telephones connected to it has been digitized, allowing multiple telephones to be connected to a common line and exchanged with each individual telephone. A method of time-division multiplexing transmission of information is being considered.

There are two types of signals to be transmitted via a transmission path. One is the communication information between terminals * (e.g. voice, etc.)
The channel for transferring this is called the B channel (voice or data information channel). the other one is,
This is a control signal for monitoring or controlling the operating state of the terminal between the terminal and the main device, and the channel for transferring this is called the D channel (control channel).

One of the conventional methods for realizing multiplex transmission is to provide the same number of B channels and D channels as the number of accommodated terminals on a transmission path, and to fixedly allocate one channel to each terminal.

Furthermore, the basic method, which is scheduled to be adopted in another conventional method that realizes multiplex transmission (Network),
There is an access interface. In this system, only one D channel is provided on a transmission path, and a plurality of terminals acquire the right to transmit to the D channel while performing competitive control with each other. Signal reception from the D channel is performed by determining whether the address information matches. By exchanging control signals over the D channel, a large number of terminals can share a limited number of B channels and communicate efficiently.

[Problem that the invention seeks to solve]

By the way, the above-mentioned method of providing the same number of B channels and D channels as the number of accommodated terminals and fixedly allocating one channel to each terminal is a simple method that does not require control over channel allocation. , there are the following problems.

■ The bandwidth (bit rate) that can be used by one terminal is B
Limited to one channel.

■ In relatively low-traffic applications, many B channels are left unused, making it impossible to effectively utilize the bandwidth on the transmission path.

■ The bit rate of the signal transferred through the transmission line increases.

In addition, basic
Although the access interface method can solve the above problems, the processing required of the terminal and the main device becomes complicated, making it difficult to realize economically.

The purpose of the present invention is to solve the above problems by
Control of signal transmission and reception on the D channel is simple,
Another object of the present invention is to provide a terminal line setting control method for a time division multiplex transmission system that improves the efficiency of using B channels.

[Means for solving problems]

The first aspect of the present invention is a terminal line setting control method for a time division multiplex communication system that controls the setting of communication channels of a plurality of terminals connected to a main device by a time division multiplex transmission path by transmitting and receiving control signals. The basic transmission frame transmitted on the time division multiplex transmission path contains information bits that indicate the status of call control signal transmission and reception of the main device for all the terminals, and multiple control signals that should be individually assigned to each terminal. When the information focus is the first value, each terminal receives and stores the control signal time slot number specified by the main device for each terminal, and the information bit is When it is the second value, each terminal executes transmission and reception of the control signal using this control signal time slot if the transmitted control signal time slot number is already held in its own terminal, If not received, send a request signal to the main device using the assigned control signal time slot, and after receiving the control signal time slot number assignment from the main device, use this control signal time slot. It is characterized by transmitting and receiving the control signal.

A second aspect of the present invention is a terminal line setting control method for a time division multiplex communication system that controls communication channel settings of a plurality of terminals connected to a main device by a time division multiplex transmission path by transmitting and receiving control signals. A transmission frame transmitted to a time division multiplex transmission path includes information bits that indicate the status of call control signal transmission and reception of the main device to all the terminals, and a plurality of control signals that should be individually assigned to each terminal. A multiframe is constructed by concatenating a plurality of basic transmission frames including time slots, and the main device transmits a signal to be received by all the terminals at least one first common time slot node and each terminal. and at least one second shared time slot to be individually assigned to each terminal, and when the information bit is the first value, each terminal receives a control signal time designated by the main device for each terminal. When the slot number is received and stored, and the information bit is the second value, each terminal receives the time slot/node number for the transmitted control signal if it is already stored in its own terminal. Transmission and reception of the control signal is executed using the time slot, and if the control signal is not received, a request signal is sent to the main device using the allocated control signal time slot, and the control signal time slot node number from the main device is sent. After receiving the allocation, the control signal is transmitted and received using this control signal time slot.

Moreover, in the wood brush and the second invention, it is preferable that the time division multiplex communication system is a button telephone system.

[For production]

The present invention provides that the transmission frame includes information bits that indicate the status of call control signal transmission and reception by the main device for all terminals, such as telephones, and a plurality of control signal time slots and nodes that should be individually assigned to each terminal. and when the information bit is, for example, "0", each terminal receives the control signal time slot number specified by the main device for each terminal and stores it in its storage means; When the node is "l", if the time slot number for the transmitted control Il signal is already held in the own terminal, each terminal uses this time slot node for control signals to send and receive control signals. Execute. If not received, the request signal is sent to the main device using the assigned control signal time slot, and after receiving the control signal time slot/node number assignment from the main device, the control signal time slot is・Execute transmission and reception of control signals using SOTO. Furthermore, the above method can be applied similarly by concatenating a plurality of basic transmission frames to form a multiframe, and using a first shared slot shared by all terminals and a second shared time slot to be individually allocated to each terminal. is executed.

That is, the present invention divides the operation of the system into two states: an initialization state and an online state. In the initialization state, the main device allocates unique time slots to individual terminals, and in the online state, The terminal occupies the time slot to perform signal transfer, and the time slots are allocated even in the online state. Furthermore, when a multiframe is used as a transmission frame, multiple channels individually assigned to each terminal and one channel shared by all terminals are prepared as D channels, and control signals are exchanged via the D channel. B channels can be assigned to terminals as needed.

In this way, a relatively small number of B channels can be shared by a large number of terminals to improve B channel usage efficiency, and the shared D
The burden on the main device can be reduced by broadcasting commands using channels. Furthermore, a D channel is fixedly assigned to each terminal, simplifying processing related to transmission and reception of control signals.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a button telephone vtW to which the present invention is applied.

A real example is main unit 1F (MP,) IO, telephone@
(KTla) 20, (KTIb) 30, (KT2a) 4
0 and (KT2b) 50, the telephones 1) 20 and 30 are respectively connected to the main vt1) by the bus line BUS I
Similarly, telephones 30 and 40 are each connected to one unit 'WllO' by a bus line BUS2. Each of the bus lines BUSI and BUS2 is composed of two pairs of transmission lines, one pair of which is a line for transmitting signals sent from each telephone to the main device IO, and is hereinafter referred to as a T line. The other pair are lines that transmit signals sent from the main device 10 to each telephone,
Hereinafter, it will be referred to as R&I.

On the bus line, speech signals and control signals are time-division multiplexed and transmitted. That is, when transmitting signals on a bus route, a fixed time (for example, 125 μs) is defined as a basic unit, and a plurality of time slots are defined within that time. A plurality of these time slots are prepared for transmitting call signals and for transmitting control signals, and communication between the main device and each telephone is realized by appropriately allocating these time slots according to the telephone.

Since the configurations of the telephones in FIG. 1 are all the same, the configuration will be explained using telephone 20.

Telephone@20 includes a transmission path control circuit (TRC) 23, a speech circuit (SPC) 26, a telephone control circuit (KTC) 27, a telephone number holding circuit (TENR) 2B, a control channel holding circuit (DCR) 24, and a speech channel number. Holding circuit (
BCR)25. The transmission control circuit 23 sends a signal to the T line via the line driver (DRV) 21,
A signal from the R line is received via a line driver (RCV) 22. All signals transmitted on R1) are input to the SIN terminal of the transmission control circuit 23. On the other hand, the signal transmission from the line driver 21 is controlled by the outputs P and H of the transmission control circuit 23, and only during the period when the output EN is "1".
An output signal from the 5OUT terminal of the transmission control circuit 23 is applied to the T line. While the output EX is rOJ, the output terminal of the line driver 21 is in a high impedance state.

The communication circuit (SPC) 26 includes a transmitter/receiver (H3) 26a and an analog/digital converter (A/D) 2 for audio signals.
The digital input/output terminal of the analog/digital converter 26b is connected to the transmission control circuit 23 via the audio information line BL.

The telephone control circuit (KTC) 27 is mainly composed of a microprocessor (KTP) 27a, and has a line selection button,
Various buttons such as function buttons and dial buttons (KPY
) 27b, as well as detecting the line lamp,
Display circuit (D
SP) 27c. Also, microprocessor 2
7a is connected to the transmission control circuit 23 by a control signal line OL, and transmits and receives control signals to and from the main device IO via this line.

Furthermore, the telephone control circuit section 27 includes a line data table (LDT) 27d for storing which actual line each line selection button/line lamp corresponds to. The data to be stored in the line data table 27d is transferred from the main device 1o at the stage of system initialization.

The telephone number holding circuit (TENR) 28 is a circuit for setting and holding an identification number TEN unique to the telephone, and can be constructed using a mechanical contact switch or a non-volatile memory. All telephones in the system are assigned different identification numbers TEN. The information held in the telephone number holding circuit 28 is processed by the microprocessor 27a.
is input.

The control channel number holding circuit (DCR) 24 is a register for specifying the number of the control signal time slot that can be used by the telephone, among the time slots multiplexed on the bus line. When the microprocessor 27a sets a predetermined number in the control channel number holding circuit 24, the transmission control circuit 23 takes in this information. As a result, control signals exchanged between the microprocessor 27a and the transmission control circuit 23 are transmitted on the bus line using the designated time slot.

The speech channel number holding circuit (BCR) 25 is a register for specifying the number of the speech signal time slot that can be used by the telephone, among the time slots multiplexed on the bus line. When the microprocessor 27a sets a predetermined number in the communication channel number holding circuit 25, the transmission control circuit 23 takes in this information. As a result, the communication signal exchanged between the communication circuit 26 and the transmission control circuit 23 is transmitted on the bus line using the designated time slot.

As is clear from the above description, each telephone selects a predetermined time slot from among the multiple control signal time slots and speech signal time slots multiplexed on the bus line under the control of the microprocessor within the telephone. It is possible to select and transmit and receive call signals and control signals to and from the main device 10.

The main device (ME) 10 includes a bus control circuit (BCCI) 14
and (BeO2) 15, communication path switch (SW) 13
, central office line trunk (TRKI) 1) and (TRK2) 1
2 and a main control section (CC) 16.

Bus control circuit (BCCI) 14 and (BeO2) 15
are arranged corresponding to the bus lines BUS1 and BUS2, respectively, and in FIG. 1, a bus control circuit 14 is used for the bus line BUS1, and a bus control circuit 15 is used for the bus line BUS2. Each bus control circuit 14, 15 sends and receives multiplexed call signals to and from the call path switch 13 via the highways HWI and HW2, and also sends control signals to the main control unit via an internal data line DB. 16. In addition, the bus control circuit 14.15
The telephone 20. is multiplexed on the bus line BUSI BUS2 by transmitting and receiving telephone calls and control signals within the main device 10.
30. Send and receive between 40 and 50. bus line BU
There is a one-to-one correspondence between time slots for communication signals on SI and Bus2 and time slots on the highway.

The control 7 open signal transferred on the internal data lines DBI and DBZ includes, as address information, the number of the control signal time slot to which the signal is transferred on the bus line BUSi BUS2.

The bus control circuit 14.15 is connected to the bus line BUSi BUS2
If a control signal is received from the bus control circuit 14.15
adds the time slot number in which the received signal was present to the actual data and sends it to the main control unit 16 via internal data lines DBI and DB2. Conversely, when transferring a control signal from the main control section 16 to the bus control circuit 14.15, the main control section 16 adds the time slot number on the bus line BUS1 or BUS2 that should not be sent to the actual data and performs bus control. circuit 14
．． Notify 15. The bus control circuits 14, 15 send out the transferred signals to the corresponding time slots. In this way, the main control section 16 can specify a telephone to be controlled and output a control signal.

The central office line trunks (TRKI) 1) and (TRK2) 12 are
It executes the opening of a DC loop for the office lines COI and CO2, sending out dial signals, etc. according to instructions from the main control section 16, and notifies the main control section 16 of the detection results of incoming signals, etc. Further, the audio signal is converted into analog/digital data and exchanged with the communication path switch 13.

The main control unit (CC) 16 is composed mainly of a main processor (MP) 16a, and manages system data and controls the operation of each part of the system. System data includes telephone identification signal table (TENT) 16b, control signal time slot management table (DCT) 1601, call signal time slot management table (BCT) 16d, and telephone identification number TEN/telephone housing position number LEN conversion table (NXT). 16e. The telephone identification number table 16b is configured using the identification number TEN as an address, and holds the following information.

■ Operating status of the telephone with the relevant identification number TEN (in operation, moving, unregistered).

■　BUS number of the bus line that the phone is connected to.

■ Control signal time slot number assigned to the relevant bus line.

■ Information on function assignments for buttons and lamps on the phone.

■ Other service-related data (such as speed-dial number information).

Control signal time slot management table (DCT) 16
An example of the configuration of c is shown in Table 1. The control signal time slot management table 16c includes bus 1). The bus number is used as an address, and each address is configured with a control word that corresponds to one bit for each time slot for control signals on the bus line, and it is possible to distinguish between used and unused time slots. Each bit is 1 (used), 0 (unused)
is stored by. When using the transmission frame shown in FIG. 2, which will be described later, the word length of the control word is 23 bits. Table 1 shows examples corresponding to this.

The main processor (MP) 16a allocates individual time slots for control signals to each telephone at the system initialization stage in order to be able to send and receive control signals to and from each telephone. After this control is performed, the combination of bus line BUS number and time slot number DCN becomes telephone identification number T.
There will be a one-to-one correspondence with EN. The former set of numbers is referred to as a telephone accommodation position number LEN. The correspondence relationship between these two is the telephone identification number TEN and the telephone accommodation position number L.
It is stored in the EN conversion table 16e.

Call signal time slot management table (BCT) 16
An example of the configuration of d is shown in Table 2. The communication time slot management table 16d is configured by using the bus line BUS number as an address, and arranging a control word in which each address corresponds to one bit for each control signal time slot on the bus line. The distinction between used and unused time slots is stored by each bit of 1 (in use) or 0 (unused).

When using the transmission frame shown in FIG. 2, which will be described later, the word length of the control word is 8 bits. Table 2 shows examples corresponding to this.

(Hereinafter, this page margin) An example of the frame structure of the signal transmitted on the bus lines BUSI and BUS2 in Figure 1 is shown in Figure 2
Tables 1 and 3 show the results. Figure 2 (al shows the frame structure of the R line, TSBRO to 7 are time slots for audio signals, TSDR is a time slot for control signals,
SF is a time slot for frame signals, TSS is a time slot for system control signals, and TSG is a time slot for guard bits. frame repetition period,
In other words, as shown in Figure 2 (the time from the beginning of al to the end is 1
The time is 25 μs, and 128 bits of information exist during this time.

The audio signal time slots TSBRO to 7 each consist of 8-bit audio information (br O”br 7 ),
It is used to transmit audio PCM codes or digital data.

The control signal time slot TSDR consists of 10 bits and is used to transmit telephone control signals from the main device 10 to each telephone. More specifically, this IO bit is an 8-bit control m! (bro”-br
7), consists of a control word parity bit p and synchronization status indication pins l-s.

The guard bit time slot TSG is inserted between the valid information time slots, and contains 6 bits worth of guard bits (
gbO to gb5) are transmitted. Originally, this time slot was used to ensure timing so that information transmitted in adjacent time slots on the T line would not overlap with each other, but it was also used for the purpose of transmitting additional information from the clay W10 to each telephone. It is also possible to use

The system control signal time slot TSS is
Consisting of the DE bit for displaying the operating state of the main control unit 16 in O and the timing bits (rt O to r(3)) for notifying various timing information. It also serves as a guard bit between slot TSBR7 and control signal time slot TSDR.

In the frame signal time slot TSF, the number of the frame expressed as a 7-bit binary number (fO to f6) is transmitted. This part is time slot 1' SDR for control signal and time slot TSBR for speech signal.
It also serves as a guard bit between O's.

Table 3 shows the multi-frame structure of the R line and the information transmitted by each time slot. A multi-frame consists of 96 consecutive frames.

The frame signal time loft TSFO value (frame number) is "0" in the first frame, and is incremented sequentially thereafter.
It becomes "95" in the last frame. By identifying this frame number, the phone can establish frame and multiframe synchronization.

(Hereinafter, this page margin) BRO~7 are time slots TSB for audio signals.
It constitutes a channel for voice or data information (B channel) transmitted by RO to 7.

The most common use of the B channel is to have the phone use one time slot in each frame, transmitting an 8-bit code in the same time slot every frame.
This is a usage that provides a transmission speed of 4 kbps. In addition, one phone can use multiple time slots,
High-speed transmission such as 128kbps, 192kbps, etc.
) can also be provided.

Since the bit string gb O-gb 5 transmitted in the guard bit time slot TSG is a signal that is ignored by the telephone, it can be set to any value.

There are 96 control signal time slots TSDR in one multiframe, but here, 24 time slot groups (24 D
Channels: DRO to DR23) are defined, and control signals are transmitted through each channel. The DRO channel is a special channel used for a purpose different from other channels, and is called a broadcast channel. That is, signals transmitted over the DRO channel are received and processed as valid signals by all telephones connected to that bus line. On the other hand, the other channels DR1 to DR23 are individually assigned to telephones connected to the bus line, and one telephone exclusively uses one channel. Other channels are ignored and not passed on to processor 27 within the phone. A control method for allocating the D channel to a telephone will be explained later.

Valid information for each D channel consists of 4 bytes. Table 4 shows an example of how to use these 4 bytes. A transmission control signal used for error control etc. is placed in the first byte. The second byte is a command code that instructs the control content, and the third byte is a command code that instructs the control content.
, Parameter data 1.2 necessary for executing the control specified by the command code is placed in the fourth byte.

For example, a command code can represent a "display instruction", and parameter data can represent a maximum of 2 bytes of "display content".

FIG. 2(b) shows the T-line frame structure in correspondence with the R-line frame structure. The T line has a time slot in which the telephone can send signals) TSBTO~7
(for voice signals) and TSDT (for control signals), each time slot is used in pairs with a corresponding time slot on the R line. That is, each telephone transmits a signal on the T line in the same time slot that it receives a signal from the R line.

The signal sent to the audio signal time slots TSBTO~7 is audio information II! Before the 8 bits (bto to bt7), there is a 2-bit synchronization bit 5to (= rlJ), 5
This is a configuration in which tl (=rOJ) is added. On the other hand, the signal sent to the control signal time slot TSDT has a configuration in which a synchronization bit 5tO1stl is added before the control signal 8 bits (dt O-dt7) and the parity pin (1 bit). An example of the transmission waveform when these signals are transmitted on the T line is shown in Figure 2 (C1). Manchester code is used as the transmission code. During the period when all telephones are not transmitting signals on the T line (t1),
The line-to-line potential difference of the T line is zero. When the phone starts sending out signals, the start bits are (+V, -■, -V, +
V), followed by valid information. The reception of the T-line signal in the bus control circuits 14 and 15 of the main device 10 is activated when the line-to-line potential difference changes from zero to a state in which a significant potential difference exists due to the synchronization bit.

If the line length from the main device 10 to the telephone is limited to a certain value or less, the time from when each time slot is sent from the main device 10 to R1 until the corresponding signal is received from the R line is constant. Limited to below value. From this,
The main device 10 can identify the type of the received signal by regarding the signal received within this time as the signal corresponding to the transmitted time slot.

An example of a typical operation of a key telephone system configured using the main device, telephone set, and transmission frame described above will be described next.

First, based on the flowchart shown in Figure 3, do you know if it is made of earthenware? &
The system initialization operation performed immediately after power-on of the 10 will be described. When the main power source of the main unit 10 is turned on and the main unit 10 enters the operating state, it starts transmitting the frames shown in Table 3 to the R line. At this time, the main processor 16a sets the value of the DE bit to "0" to notify the telephone that it is in the process of controlling system initialization.

Each telephone receives the frames and establishes synchronization by detecting the frame number that appears periodically. This makes it possible to grasp which position in the multiframe the signal received at each point in time corresponds to. Once synchronization is established, the value of the DF bit is first checked and the value is rOJ.
By this, the control from the main device 10 is waited for (the operation when DB = "1" will be described later)
.

After securing the time required for each telephone to establish synchronization, the main control unit 16 of the main device 10 refers to the telephone identification number table 16b and sequentially selects the telephone identification numbers TEN registered as "compatible telephones available" therein. and sends out the rTEN_INQUIRY signal through the DTO channels of all bus lines in the system. The "rTEN inquiry" signal includes the telephone identification number TEN as parameter data.

Each telephone receives this signal and uses a microprocessor 27
a determines whether the identification number TEN in the received signal matches the number held in the telephone number holding circuit 28 of its own telephone. If they match, the microprocessor 27a r ”
r' EN match'' signal to the master unit IO via the DTO channel. If there is a mismatch, the phone is not activated and waits for the next signal to be received.

When the main control unit 16 of the main device 10 receives "rTEN match" from any telephone in response to the "rTEN inquiry", it starts an operation for allocating a control channel to that telephone. First, when a response is returned, the bus line BUS number to which the telephone is connected is identified, and the control signal time slot management table 16 is determined based on that value.
Search for c and find an unused times ml sort. If there is an unused time slot, an "rDcN allocation" signal containing the time slot number DCN and telephone TM identification number TEN as parameter data is sent via the DRO channel.

A telephone that satisfies the above-mentioned telephone identification number TEN matching condition can recognize a channel that can be used by the own telephone by receiving this signal. The microprocessor 27a causes the control channel number holding circuit 24 to hold the allocated time slot number, activates the transmission and reception of control signals for this time slot, and sends out the rDCN confirmation signal via this channel in response to the above signal. do.

When the synchronization of the relevant D channel on the T line is established, the main control unit 16 sets the corresponding bit on the control signal time slot management table 16c to "1" and registers it as being in use, and the corresponding bit on the R line The value of the S bit of the D channel is set to "1" to display the synchronization establishment state. Furthermore, the main control unit 16 refers to the telephone identification number table 16b, and assigns the bus line BUS number to which the telephone is connected and the assigned time slot number to the address corresponding to the telephone to which the time slot number DCN assignment has been completed. In addition to writing and storing the number DCN, the telephone identification number TEN/telephone housing position number LEN conversion table 1
Register control data in 6e. The main control unit 16 also reads function assignment information for buttons and lamps from the telephone identification number table 16b, and transfers this as initial setting data to the telephone through the D channel.

The initial setting data includes information on the allocation of the central line number to the central line button number on the telephone and information on the allocation of the central line number to the central telephone lamp number on the telephone.

The telephone registers the received initial setting data and line data in the line data table 27d, and when the reception is completed, it enters a standby state. During this time, the telephone waits for the main control unit 16 to start accepting call processing while constantly sending an rNOP (free m) J signal to the T line to prevent synchronization.

A The above series of steps completes the control of time slot number DCN allocation to one telephone set.

The main control unit 16 continues this control while sequentially incrementing the value of the telephone identification number TEN. When the above control is completed for all the numbers registered as "telephone present" in the telephone identification number table 16b, a unique time slot number DCN is assigned to every telephone in the system. This number is set to a different value between telephones connected to the same bus line (however, if the bus lines are different, there are telephones having the same time slot number DCN). This shows that it is possible to match the combination of the bus line BUS number and time slot number DCN with the telephone identification number TEN in a one-to-one correspondence.

Note that if no response from the telephone is detected for a certain period of time in response to the "rTEN inquiry from the main control section 16," the main control section 16 will stop the process related to the telephone identification number TEN, and start processing for the new telephone identification number TEH. Start. At this time, telephones that do not respond are ignored as not being incorporated into the system.

When the main control unit 16 completes the above procedure, it enters the exchange processing service acceptance state, and indicates this by setting the DE bit of the R line to r.
Notification is sent to all telephones by sending it as lJ. From then on, the main control unit 16 always uses DE during normal operation of the system.
Keep bit at rlJ.

On the other hand, in a telephone, the microprocessor 27afJ<DE
-Ill is detected to enable various inputs such as dials, line buttons, function buttons, etc., and when an input signal from a user's operation is detected, a control signal is sent to the T line through the assigned D channel. In addition, instructions from the main control unit 16 are transmitted to the broadcast channel (DRO) and the individually assigned channel (DRO).
R+, where i=1 to 23), and performs an operation predetermined by the program.

The operation of the entire system will be described by taking as an example a case where the telephone 20 makes an outgoing connection to the central office line C01. here,
It is assumed that the telephone 20 has a telephone signal number TEN of "10" and a control signal time slot number DCN of "1".

■ When the telephone 20 goes off-hook and the central office line button (button number 1) corresponding to the central office line CO1 is pressed, the microprocessor 27a sends out control signals of "off footer" and "button number 1 pressed" through the DTI channel. .

(2) In the main device 10, the main control section 16 receives the above signal via the bus control circuit 14. A time slot number is added to the signal supplied from the bus control circuit 14 to the main control unit 16, and based on this and the bus line BUS number, the main control unit 16 converts the telephone identification number TEN to the telephone accommodation position number LEN. Index the table 16e and call the telephone 2
Determine the telephone identification number TEN of 0.

(2) The main control unit 16 searches the telephone identification number table 16b using the above values and determines what the central office line number corresponding to button number 1 is.

■ Based on this result, the main control unit 16
and closes the loop circuit to the station line COI.

■ The main control unit 16 transmits the ``office line COI in use signal'' through the DRO channels of all the bus lines, and the ``office 1iIcO1 self-use'' signal through the DPI channel of the bus line BUS I to which the calling telephone 20 is connected. Send each.

- Of the above, the first signal, the "office line COI in use" signal, is received by all telephones in the system. Each telephone determines whether or not the button and lamp corresponding to the central office line CO1 are present in the line data table 27d.
If there is a corresponding one, the lamp is turned on steadily.

On the other hand, the second signal, the "office line C01 privately used" signal, is received only by the calling telephone 20.

In response to this signal, the microprocessor 27a of the calling telephone 20 turns on the central office line CO, which has been set to the steady lighting state.
Change the station line lamp corresponding to 1 to a blinking display indicating the self-use status.

■ The main control unit 16 refers to the call signal time slot/node management table 16d, checks the usage status of the call signal time slot on the bus line BUSI to which the calling telephone @20 is connected, and checks the usage status of the call signal time slot on the bus line BUSI to which the calling telephone @20 is connected. After searching for a time slot, it sends the "time slot allocation J signal for call signal" via the DRI channel of the bus line IBUSI, and registers the corresponding bit on the time slot management table 16d for call signal as being in use. , and connects this communication signal time slot to the central office line trunk 1) by driving a speech path, i.e., 13.

(2) The above-mentioned "time slot allocation for call signal" signal is received only by the calling telephone 20. In response to this signal, the microprocessor 27a causes the designated call signal time slot number to be held in the call channel number holding circuit 25, and sets up a call bus. As a result, call @20
This means that a call bus has been set up between the station line CO1 and the office line CO1.

A more detailed explanation will be given below regarding the operations of (1) and (2) above, which show the display control of the office line lamp. Which of the two signals sent by the main control unit 16 in (2) is received first by the calling telephone 20. It is generally considered that this is uncertain. As mentioned in ①, [Station vAC
If the "O1 in use" signal is received first, lamp control may be executed in the order in which it was received, but if this order is reversed, a problem will occur. To solve this problem, the following two methods can be taken. One is the main control section 1
6 is a method in which the above two signals are sent at an appropriate time interval. In this case, the microprocessor 27a only has to process the signals unconditionally in the order in which they arrive. The other is a method in which when control signals related to the same station line lamp G are received redundantly from the broadcast channel DRO and the individual channel DPI, the signal from the individual channel is always given priority and processed regardless of the order of arrival. It is. In this case, the main control unit 16
This eliminates the need to strictly control the sending order of the two signals.

Next, during system operation, the phone @20 was connected to the bus line BUSI.
The operation when the bus line BLIS2 is disconnected from the bus line BLIS2 and connected to another bus line BLIS2 will be explained.

Assume that this telephone 1) 20 has been given "1" as the time slot number 1) CN. When the 1i phone 20 is disconnected from the bus line BUS 1, the main device 10
I-channel signal reception is interrupted, making it impossible to detect the start bit. The bus control circuit 14 sets the 3 bits of the DPI channel to "0" when this state continues for a certain number of times (for example, 4 times) or more, and also sets the corresponding bit on the control m signal time slot management table 16c. is set to "0" to indicate the unused state of this channel.

Furthermore, the telephone identification number TEN and the telephone accommodation position number L
Refer to the EN conversion table 16e to determine the telephone 4IIIi separate number TEN of the telephone 1) 20, set the telephone presence/absence identification in the telephone identification number table 16b to "none", and set the telephone m identification number TEN. The display data on the telephone housing position number LEN conversion table 16e is deleted.

Assume that when this telephone 20 is connected to the bus line BUS2, four telephones are already operating on the bus line BUS2, and time slot numbers DCN 1 to 4 are in use (see Table 1). .

When this telephone l120 is connected to the bus line BUS2 and starts receiving signals, the DE bit of R41J: is rlJ because the system is already in operation. 1
Talking @20, this causes the above system initialization (DE
-rOJ) can be identified as being in a different state. In this case, phone 1) 20 is connected to the DTO channel by phone IvIh.
A "time slot number DCN request" signal containing the separate number TEN as a parameter is sent.

When this is received by the main device 10, the main control unit 16 checks the telephone identification number table 16b and confirms that the telephone presence/absence information is not "present". This is to prevent multiple telephones having the same telephone identification number TEN from existing in the system.

Once confirmed, the bus line BLIS2 corresponding section of the time slot management table 16c for the 1g is referred to, and an unused time slot number DCN is searched for. In this case,
DCN=6 is unused and the corresponding bit is rOJ. Based on this result, the main control unit 16 sends out a ``time slot number DCN assignment'' signal, and control thereafter proceeds in the same procedure as at the time of system initialization. When the series of procedures is completed, the telephone set 20 is already in the DE-rlJ state, so that the telephone set 20 is immediately ready to receive service.

In the above process, the service data transferred from the main control unit 16 of the main device 10 when the telephone 20 is reconnected is read from the same telephone identification number table 16b, so even if the connection point is moved, the service data is the same as the original one. It is possible to operate under service conditions. Furthermore, even when a completely new telephone is connected to an operating bus line, it is possible to incorporate it into the system and operate it while the system is in operation, by the same operation as in the second half of the above.

On the other hand, if two telephones are connected to the same bus line at the same time, both telephones will simultaneously respond to the broadcast D channel.
There is a possibility that the "time slot number DCN request" signal will start to be sent. In this case, both signals will interfere with each other on the bus line, and the signal received by the main device 10 will be a combination of both signals. Here, since each telephone is assigned a different telephone aiali number TEN, the main device 10 cannot receive the original normal signal.

As a result, the telephone cannot obtain a time slot for control signals using the rDCN allocation signal. If this condition continues for a certain period of time, the telephone will wait a waiting time determined based on the value of the telephone identification number TEN (for example, (TEN value) x [time of 4 frames]). The "rDCN request" signal is sent out again. In this way, each telephone is guaranteed to transmit a signal without causing interference with other telephones, and can normally obtain a DCN assignment.

Above, in order to simplify the explanation, the number of bus lines connected to the main device 10 has been limited to two bus lines BUSI,2, but the telephone i identification number table 16b, the control signal time slot management table 16c, By expanding the address space of the time slot management table 16d for call signals and the telephone identification number TEN/telephone housing position number LEN conversion table 16e, the same system as described here can be applied to a system accommodating a larger number of bus lines. techniques can be applied.

In addition, although the method of configuring the transmission frame has been explained assuming that the frame period is 125 μs, the number of B channels in the frame is 8, and the number of D channels is 1, the method of the present invention can also be applied to configurations in which these values are changed. Easy to apply. For example, as shown in FIG. 4, a method can be considered in which the frame period is set to 250 μs and the amount of information (number of bits) in the channel is doubled while keeping the number of B channels in the frame at 8. If this method is adopted, the guard time between channels is shown in Figure 2 (C1
can be increased compared to tl. As a result, the amount of time available for overlapping signals between channels increases,
It becomes possible to increase the length of the line to the telephone.

Note that although the above description has taken up a telephone as a terminal, it is similarly applicable to other terminals having the same means as a telephone.

〔Effect of the invention〕

As explained above, by applying the method of the present invention, by assigning unique terminal numbers to all telephones (terminals) in the system, a common D channel is used when the telephones start operating. Each telephone can have a fixed allocation of an individual D channel. After the telephone is assigned this assignment, it can occupy the corresponding channel and send and receive control signals. As a result, when the system is on-line, it is possible to mechanically execute control signal transmission and reception processing, reducing the processing burden on the processors of the main device and the telephone, and achieving high throughput signal transfer.

In addition, by issuing simultaneous commands using the common D channel from the main device to the telephone, it is possible to reduce the frequency of signals sent from the main device processor to the telephone, which is also effective in reducing the processing load on the main device processor. Become a means.

Furthermore, since the B channel used by a telephone can be arbitrarily specified from the main device by exchanging control signals through the D channel, it is possible to connect more telephones than the number of B channels to the transmission line to make effective use of the B channel. Can be done. Furthermore, it is possible to use a plurality of B channels simultaneously with one telephone, and high-speed information transfer can be realized.

As described above, according to the present invention, it is possible to reduce the number of wiring cables to a telephone set, and at the same time, achieve the above-mentioned performance improvements with an economical configuration, which has a very large effect. It is.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a button telephone device to which the present invention is applied. FIG. 2 ta) and lbl are explanatory diagrams showing an example of a transmission frame structure. FIG. 2 (01 is a waveform diagram showing one embodiment of the signal. FIG. 3 is a flowchart for explaining the operation of FIG. 1. FIG. 4 is an explanatory diagram showing another embodiment of the transmission frame structure. 10... Main equipment (ME), 1)... Office line trunk (TRKl), 12... Office line trunk (TRK2)
, 13... Communication path switch (SW), 14... Bus control circuit (BCCl), 15... Bus control circuit (B
eO2), 16... Main control unit (CG), 16a ・
"Main processor (MP), 16b...Telephone identification number table (TENT), 16c...Time slot management table for control signals (DCT), 16d...Time slot management table for call signals (BCT),
16e...Telephone identification number TEN/telephone accommodation position number LEN conversion table (NXT), 20...Telephone (KT l a), 21... Line driver (D
RV), 22... line receiver (RCV), 23.
...Transmission control circuit (TRC), 24...Control channel number holding circuit (DCR), 25...Speech channel number holding circuit (BCR), 26...Speech circuit (S P
C), 26a... handset (HS), 26b...
・Analog-digital converter (A/D), 27...
Telephone control circuit (KTC), 27a -- Microprocessor (KTP), 27b... Various buttons (K
EY), 27c...Display circuit (DSP), 27d.
...Line data table (LDT), 2B...Telephone number holding circuit (TENR), 30...Telephone (KT
1 b), 40...Telephone i! (KT2 a),
50-"Telephone (KT2b), BL...Voice information line, Busl, BtJS2...Bus line, C01, GO
2... Office line, DBI, DB2... Internal data line, D
L...Control signal line, EN...Output, HWI, HW2
...Highway, SIN, 5OUT...terminal. 18 Kaisho ('12-271589 (16) Tokukai gQ
G 2-271589 (18) - all 1 ri c+ 夾 ＼

Claims (3)

[Claims] (1) In a terminal line setting control method for a time division multiplex communication system that controls the setting of communication channels of a plurality of terminals connected to a main device by a time division multiplex transmission line by transmitting and receiving control signals, the above time division multiplex transmission line The basic transmission frame to be transmitted includes an information bit (DE) that indicates the status of call control signal transmission and reception of the main device to all the terminals, and a plurality of control signal bits that should be individually assigned to each terminal. time slots (dr0 to dr7), and when the information bit is the first value, each terminal receives and stores the control signal time slot number designated by the main device for each terminal, and When the information bit is the second value, each terminal transmits and receives the control signal using this control signal time slot if the transmitted control signal time slot number is already held in its own terminal. If it is not received, a request signal is sent to the main device using the assigned control signal time slot. After receiving the control signal time slot number assignment from the main device, this control signal time slot is executed. A terminal line setting control method for a time division multiplex communication system, characterized in that the transmission and reception of the control signal is performed using the above. (2) In a terminal line setting control method for a time division multiplex communication system that controls communication channel settings of a plurality of terminals connected to a main device by a time division multiplex transmission line by transmitting and receiving control signals, the time division multiplex transmission line described above The transmission frame to be transmitted includes information bits indicating the state of call control signal transmission and reception by the main device to all the terminals, and a plurality of time slots for control signals to be individually assigned to each terminal. A multi-frame is constructed by concatenating a plurality of basic transmission frames including at least one first shared time slot (DRO) in which the main device sends a signal to be received by all the terminals, and a signal transmitted to each terminal individually. at least one second shared time slot (DR1 to D
R23), when the information bit is a first value, each terminal receives and stores the control signal time slot number designated by the main device for each terminal, and when the information bit is a second value, When the value of , each terminal uses this control signal time slot to transmit and receive the control signal if the transmitted control signal time slot number is already held in its own terminal, and if the control signal is not received, In this case, send a request signal to the main device using the assigned control signal time slot, and after receiving the assignment of the control signal time slot number from the main device, use this control signal time slot to perform the above control. A terminal line setting control method for a time division multiplex communication system characterized by transmitting and receiving signals. (3) A terminal line setting control method for a time division multiplex communication system according to claim (1) or (2), wherein the time division multiplex communication system is a button telephone system.