JP2761879B2 - Transmission control system for private branch exchange - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a transmission control method for a private branch exchange that accommodates a plurality of ISDN terminal devices on the extension side.

[Prior art] In recent years, ISDN (Integrated Server) that digitizes a communication network (telephone network) including a subscriber transmission section to improve the economy and quality of the network and provide various services.
ces Digital Network) is being envisioned, and its standardization work is being carried out by the CCITT (International Telegraph and Telephone Consultative Committee).

In the ISDN, the connection between the network and the terminal equipment on the user side is in the form of a bus. According to the current CCITT recommendations,
There are two types of user / network interfaces in N, a basic interface and a primary group interface.

FIG. 5 shows a configuration example on the user side when the basic interface is used.

In ISDN, a passive type main wiring bus MB is connected to a user side of a network terminating device NT1 which provides a basic interface for connecting a terminal device to a network.

, ST8 are connected to the main wiring bus MB via sockets ST1, ST2, ..., ST8. Here, the maximum number of ISDN terminal devices that can be connected to these main wiring buses MB is limited to eight.

As the ISDN terminal devices TE1 to TE8, in addition to a voice terminal device such as a digital telephone, a G4 facsimile device,
A non-voice terminal such as a teletex or a personal computer is connected. Information exchanged between these digital telephones, the G4 facsimile machine, the teletex and the personal computer is added with identification information capable of identifying the type of each terminal.For example, the digital telephone makes a call from the G4 facsimile machine. Such as inconvenience.

The main wiring bus MB is physically a four-wire transmission line of two transmission / reception circuits, but has two information channels B1 and B2 (B channel) with a channel speed of 64 kbps and a channel speed of 1
One signal channel D of 6 kbps is multiplexed.

Here, the information channels B1 and B2 can be collectively used as one information channel of 128 kbps, and one information channel can be divided into subchannel speeds of 32 kbps, 16 kbps, and 8 kbps. Although limited, the D channel can be used as an information channel.

In addition, when one of the ISDN terminal devices is connected to the main wiring bus MB and a call request is made for the first time, another ISDN terminal device connected to the same main wiring bus MB newly establishes an ISDN network. At this time, unique identification information (terminal end point identifier: TEI) for the main wiring bus MB is set to the newly connected ISDN terminal device so that the connected ISDN terminal device can be reliably identified.

Therefore, for example, the ISDN terminal device TE1 connected to the same network terminating device NT1 via the ISDN network
The same main wiring bus MB, such as transmitting information by calling E2
, And TE8 connected to each other can transmit information to each other. If the function of this ISDN network is used, an extension call function can be realized without providing a special mechanism.

However, since such an extension call function uses the switching function of the ISDN network, there is a disadvantage that the extension call is charged by the ISDN network.

In order to solve such a problem, it is conceivable to provide a private branch exchange between the network terminating device NT1 and the main wiring bus MB. However, a non-voice IS connected to the main wiring bus MB may be provided.
If the DN terminal device connects to each other by using the two information channels B1 and B2 and performs an extension call, there arises a problem that an incoming call from the ISDN network cannot be accepted.

As described above, up to eight ISDN terminal devices can be connected to the main wiring bus MB. However, when two ISDN terminal devices occupy an information channel for an extension call, the same main wiring bus MB is used. There is also a disadvantage that information cannot be transmitted by another ISDN terminal device such as a digital telephone connected to the Internet.

[Purpose] The present invention has been made to solve such disadvantages of the prior art, and has been made in consideration of an ISDN connected to the same main wiring bus.
It is an object of the present invention to provide a transmission control method of a private branch exchange that enables an appropriate extension call between terminal devices.

[Configuration] In order to achieve this object, the present invention is arranged such that information transmission between non-voice ISDN terminals accommodated in an extension is performed using a signal channel.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an ISDN communication system according to one embodiment of the present invention. In this figure, the same parts as those in FIG. 5 are denoted by the same reference numerals.

In the figure, a digital telephone DT is connected to a main wiring bus MB.
A composite terminal device CX1 for the ISDN network configured by combining L1 and the non-voice terminal NTL1, and a composite terminal device CX2 for the ISDN network configured by combining the digital telephone DTL2 and the non-voice terminal NTL2. Are respectively connected via sockets ST1 and ST2, and between the network terminating device NT1 and the main wiring bus MB, the functions of the layer 1 protocol for the complex terminal devices CX1 and CX2, and the layers 2 and 3 A private branch exchange NT2 for terminating all or a part of the functions of the protocol is provided.

The digital telephones DTL1 and DTL2 of the complex terminal devices CX1 and CX2 are
It is equipped with a function to encode and compress voice information to a data rate of 16 kbps and to transmit and receive them.
The extension calls between DTL2 and DTL2 are performed using information channels B1 and B
Done using one of the two.

Also, the non-voice terminal devices NTL1 and NT of the composite terminal devices CX1 and CX2
L2 transmits and receives data at relatively low transmission speeds, since the transmission / reception data is character data, the need for immediacy of data transmission is low, and these non-voice terminal devices NTL1, NL
Extension communication between the TL2s is performed using the signal channel D.

The complex terminal devices CX1 and CX2 perform data transmission of the digital telephones DTL1 and DTL2 by occupying 2 bits per frame of one of the information channels B1 and B2 designated by the private branch exchange NT2.

In addition, the composite terminal devices CX1 and CX2 are
If the destination address indicates a terminal device accommodated in the same private branch exchange NT2 when performing NTL2 data transmission, a signal channel is used as a communication path when making a call setup request to the private branch exchange NT2. If D is specified and the destination address indicates a terminal device on the outside line, one of the information channels B1 and B2 or the signal channel D is specified as a communication path.

With the above configuration, for example, when the operator of the composite terminal device CX1 forms a transmission file with the non-voice terminal device NTL1 and performs an extension call for transmitting the transmission file to the non-voice terminal device NTL2 of the composite terminal device CX2, Terminal device CX1
When the operator designates a transmission destination and instructs the start of an extension call, as shown in FIG. 2, a call setup message S1 is sent to the private branch exchange NT2 using the signal channel D,
Requests the setting of a communication path with the partner device.

At this time, in the call setting message S1, the address of the composite terminal device CX2 is set as the destination address, and the signal channel D is set as the request channel of the communication path.
Further, information requesting the non-voice terminal device NTL2 as the partner device is set as additional information (user / user information). In the following description, the exchange of messages for controlling the transmission procedure between the complex terminal device CX1 or CX2 and the private branch exchange device NT2 is performed using the signal channel D.

As a result, the private branch exchange NT2 sends the call setup message S
Since the destination address of the extension is specified in 1 and the signal channel D is specified in the communication path, the signal channel D
, The call setup message S2 is transmitted to the multifunction terminal CX2. The user setting information in the call setting message S1 is added to the call setting message S2.

Further, the private branch exchange apparatus NT2 sends a call setting acceptance message S3 notifying that the processing of the call has been started to the composite terminal apparatus CX1.

Thus, when the composite terminal device CX2 starts calling, the composite terminal device CX2 sends a call message S4 to the private branch exchange NT2. As a result, a call message S5 is sent from the private branch exchange NT2 to the multifunction terminal CX1.

When completing the incoming call operation corresponding to the call setup message S2, the composite terminal device CX2 sends a response message S6 for requesting / notifying the establishment of a communication path to the private branch exchange NT2.

As a result, the private branch exchange NT2 is connected to the complex terminal CX1.
And assigns the signal channel D to the communication path of the composite terminal device CX2, and sends a response message S7 to the composite terminal device CX1. Also, the private branch exchange NT2 sends a response confirmation message S8 to the composite terminal CX2.

Thus, the composite terminal device CX1 and the composite terminal device CX2
When a communication path is established between the non-voice terminal NTL1 of the composite terminal CX1 and the non-voice terminal NTL2 of the composite terminal CX2, the information transmission S9 is performed. The file is transmitted to the non-voice terminal NTL2 using a non-packet communication type user-user signaling procedure on the signaling channel D.

In the information transmission S9, a transmission control procedure for information transmission set between the non-voice terminal NTL1 of the composite terminal CX1 and the non-voice terminal NTL of the composite terminal CX2 is performed. FIG. 3 shows the state of information transmission at that time.

That is, the non-voice terminal device NTL1 sends user information US1 for setting communication conditions and the like to the non-voice terminal device NTL2, and prepares for transmission of a transmission file.

The non-voice terminal device NTL2 confirms the transmission function to be used based on the content of the user information US1, and responds to the non-voice terminal device NTL1 with user information US2 indicating that the preparation for receiving the transmission file is ready.

Thus, the non-voice terminal device NTL1 transmits the user information US3
The transmission of the transmission file is performed, and when the transmission is completed, the user information S4 indicating the end of the transmission is transmitted to the non-voice terminal device NTL2.
Send to Thus, when the non-voice terminal device NTL2 responds with the user information US5 indicating that the transmission has been completed, the transmission of the transmission file from the non-voice terminal device NTL1 to the non-voice terminal device NTL2 ends.

When the transmission of the transmission file is completed, the composite terminal device
CX1 sends a disconnection message S10 requesting release of the communication path to the private branch exchange NT2. Thereby, the private branch exchange N
T2 sends a disconnection message S11 to the composite terminal device CX2.

On the other hand, the composite terminal device CX2 sends a release message S12 for confirming the release of the communication path to the private branch exchange NT2. As a result, the private branch exchange NT2 sends a release message S13 to the multifunction terminal CX1. As a result, the communication path between the composite terminal device CX1 and the composite terminal device CX2 is released.

Further, the composite terminal device CX1 sends a release completion message S14 to the private branch exchange NT2. Thereby, the private branch exchange N
T2 sends a release completion message S15 to the composite terminal device CX2.

 This terminates the call connection.

With the above procedure, a communication path is set between the complex terminal devices CX1 and CX2, and the transmission path set between the non-voice terminal devices NTL1 and NTL2 of the complex terminal devices CX1 and CX2. Information transmission is performed according to the control procedure, and the communication path is released.

Thus, the non-voice terminal N of the composite terminal CX1
FIG. 4 shows how information is exchanged on information channels B1, B2 and signal channel D when an extension call (extension transmission) is being performed between TL1 and non-voice terminal device NTL2 of composite terminal device CX2. Shown in

In this case, an extension call using the information channel B1 is performed between the digital telephone DTL1 of the composite terminal CX1 and the digital telephone DTL2 of the composite terminal CX2, and the non-voice terminal NTL1 and the non-voice terminal NTL2 are used. , Extension transmission using the signal channel D2 is performed. That is, data transmission using a non-voice terminal device is performed while an extension call using a digital telephone is being performed.

In the following description, the data direction from the complex terminal devices CX1 and CX2 to the private branch exchange device NT2 is referred to as “up”,
The opposite direction is called “down”. Also, each data is represented in units of one frame.

At this time, as shown, assuming that the first and second bits of the information channel B1 are assigned to the digital telephone DTL1 and the third and fourth bits of the information channel B1 are assigned to the digital telephone DTL2, as shown in FIG. Sets the transmission data Ta of the digital telephone DTL1 to the first and second bits of the information channel B1 on the upstream side (hereinafter, referred to as an uplink information channel) UB1, and sets the downstream side of the information channel B1 (hereinafter, referred to as a downlink information channel) DB
The data of the first and second bits of 1 is fetched as received data Ra of the digital telephone DTL1.

Further, the composite terminal device CX2 sets the transmission data Tb of the digital telephone DTL2 to the third and fourth bits of the uplink information channel UB1, and transmits the third and fourth bits of data of the downlink information channel DB1 to the reception data of the digital telephone DTL2. Import as Rb.

Then, in the private branch exchange NT2, the information channels B1,
The B channel control unit CTB for controlling the exchange of data in B2 sets the first and second bits of the uplink information channel UB1 to the third and fourth bits of the downlink information channel DB1, and sets the third and fourth bits of the uplink information channel UB1. , 4 bits for downlink information channel DB1, 1st and 2nd
By setting the bit, information transmission between the digital telephone DTL1 and the digital telephone DTL2 is performed.

On the other hand, the composite terminal device CX1 transmits the signal UD1 addressed to the non-voice terminal device NTL2 in which the transmission data DTa of the non-voice terminal device NTL1 is set in the user information, on the upstream side of the signal channel D (hereinafter, referred to as
The signal DD1 transmitted to the own terminal via the downstream side of the signal channel D (hereinafter, referred to as the downstream signal channel) is taken in as the reception data DRa of the non-voice terminal device NTL1.

Further, the composite terminal device CX2 transmits a signal UD2 addressed to the non-voice terminal device NTL1 in which the transmission data DTb of the non-voice terminal device NTL2 is set in the user information to the uplink signal channel, and transmits to the own terminal via the downlink signal channel. DD2 transmitted to
As the received data DRb of the non-voice terminal device NTL2.

Then, in private branch exchange NT2, D channel control section CTD for performing signal control on the D channel sends out signals UD1 and UD2 received via the uplink signal channel to the downlink signal channel, respectively.

Since only one terminal device can occupy signal channel D at a time, information transmission between non-voice terminals NTL1 and NTL2 using signal channel D as a transmission path is performed in an alternate transmission format.

In this way, under the control of the private branch exchange NT2, information transmission between the digital telephone DTL1 and the digital telephone DTL2 is performed using the information channel B1, and the non-voice terminal NTL1 and the non-voice terminal Information transmission between the NTLs 2 is performed using the signal channel D.

In the above description, the details of the transmission procedure that are not directly related to the present invention are omitted.

As described above, in this embodiment, the non-voice terminal devices NTL1, NTL
Since the extension transmission between the TL2s is performed by using the signal channel D, the information channels B1 and B2 are not occupied, so that the information channels B1 and B2 can be effectively utilized.

By the way, in the above-described embodiment, the extension transmission of the non-voice terminal device is transmitted by the user / user signal procedure so that the function to be provided in the private branch exchange apparatus can be reduced. You can also. However, in that case, the private branch exchange requires a function for a packet exchange procedure.

Further, in the above-described embodiment, when the complex terminal receives a request for extension transmission from the non-voice terminal, it requests the private branch exchange for extension transmission using the signal channel D. The function of allocating a channel to the non-voice terminal device at the time can also be provided to the private branch exchange.

In this case, when there is a vacancy in the information channels B1 and B2, the vacancy can be allocated to the extension transmission of the non-voice terminal device.

In the above-described embodiment, the digital telephone constituting the composite terminal device encodes and compresses the audio information to a data rate of 16 Kbps, but the digital telephone converts the audio information to 32 Kbps.
The present invention can also be applied to a case where encoding and compression are performed at a data rate of.

In the above embodiment, the line configuration of the basic interface is used. However, the present invention can be applied to a case where the line configuration of the primary group interface is adopted.

As the non-voice terminal device, any type of data terminal device that exchanges character data and does not cause a problem of delay time can be used.

Further, in the above-described embodiment, a case has been described in which a composite terminal device obtained by combining a digital telephone and a non-voice terminal device is used. However, the same applies to a case where the digital telephone and the non-voice terminal device are separately connected. Thus, the present invention can be applied.

[Effects] As described above, according to the present invention, information transmission between non-voice ISDN terminal devices accommodated in an extension is performed using a signal channel. , And can appropriately perform an extension call between voice ISDN terminal devices that need to be established. In addition, since the free time of the information channel can be increased, the probability of setting up a call with the ISDN network is greatly increased.
It also has the advantage of realizing a DN system.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a communication system according to an embodiment of the present invention, FIG. 2 is a time chart showing an example of a transmission procedure at the time of extension transmission, and FIG. 3 is an information transmission procedure between non-voice terminals. FIG. 4 is a schematic diagram for explaining a state in which a digital telephone and a non-voice terminal device are simultaneously making an extension call, and FIG. 5 is a schematic diagram illustrating a conventional system. CX1, CX2: Composite terminal, DTL1, DTL2: Digital telephone, NTL1, NTL2: Non-voice terminal.

Claims (1)

(57) [Claims] In a transmission control system for a private branch exchange accommodating a plurality of ISDN terminal devices on an extension side, a calling non-voice ISDN terminal device accommodated on an extension line receives a non-voiced ISDN terminal device accommodated on an extension line. When making a call request to the ISDN terminal device, it requests the private branch exchange device to set a signal channel as a communication path, and the private branch exchange device transmits from the calling non-voice ISDN terminal device to the destination non-voice ISDN terminal. When there is a call request to the device, a call notification is sent to the destination non-voice ISDN terminal device, and the signal channel required to be set at the time of the call request is allocated to the communication path, and A communication path is set between the non-voice ISDN terminal device and the receiving-side non-voice ISDN terminal device, and the calling-side non-voice ISDN terminal device and the receiving-side non-voice ISDN terminal device output a signal set in the communication path. Transmission of information using channels A private branch exchange transmission control method.