JPH07321906A - Application method for digital terminal using isdn line - Google Patents

Abstract

PURPOSE:To expand and compress, on an exchange side, a compressed and multiplexed signal from a terminal side for one of channels B of 64Kbps concerning the connection application method for a digital terminal using an ISDN line. CONSTITUTION:An exchange 1 is provided with an extension/compression converting part 4, which is connected to a network terminating device 5 through a transmission line by a line trunk 2, extension-converts the compression-encoded digital signal from the line trunk 2 to an original digital signal for reception, and compression-encodes the original digital signal from the network terminating device 5 so as to send it to the line trunk 2. Then, one or plural service terminals transmitting and receiving the compression-encoded digital signal are connected to the network terminating device 5 through multiplexers 6 and 7 so as to convert the compression-encoded digital signal transmitted and received by a communication channel for ISDN through the transmission line to the original digital signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection application method for a digital terminal using an ISDN line. ISDN (Integrated Services Digital Network) is used for voice, text, data,
It aims to realize various communication services by integrating various communication media such as images and fusing them with information processing technology, and is expected to play a role as the foundation of the coming advanced information society.

In the ISDN line, the communication capability provided to the communication terminal by the digital socket is 64 Kbps.
Two channels (B channel) of (64 kilobits per second) and one control channel (D channel) of 16 Kbps (16 kilobits per second) are prepared, and higher speed communication is required. In such cases, the speeds of 1.5 Mbps (1.5 megabits per second) and 2 Mbps are also available.

Conventional telephone lines were able to transmit only a data rate of 4.8 Kbps at most, but the ISDN B channel 64 Kbps has a capacity improvement of about 10 times that of the past, and the B channel has been used up to now. Similarly, voice and facsimile can be communicated, and when different communication modes such as voice, data, and facsimile are used, when voice is sent, the voice terminal and the facsimile are correctly connected to the facsimile terminal and the sending and receiving terminals. As described above, the automatic translation function of the terminal is provided.

Currently, the terminal which can be connected to the ISDN line is I
High-bandwidth B-IS, although it is limited to those that have a protocol of layers 1 to 3 developed for SDN
TV conference terminals and TVs with specific terminals for DN
Apart from telephones and the like, it is also necessary to connect analog telephone terminals and mobile telephone terminals for narrow band N-ISDN. In particular, many mobile phone terminals and PHPs (personal handy phones), which are expected to develop rapidly in the future, are used at low speeds of 16 Kbps or less.

[0005]

2. Description of the Related Art An example of a conventional ISDN terminal connection configuration is shown in FIG.
Shown in. In the figure, 61 is a central office switch, 62 is a line trunk (LT), 63 is a transmission line interface (U point), 64 is a network terminator (NT1), 65 is a user / network interface (S / T point), 66 , 67 are digital terminals A and B.

A plurality of digital terminals 66, 67 are connected to a network terminating device 64 by a user / network interface 65, and the network terminating device 64 is connected by a transmission line interface 63 to a central office switch 61.
Connected to the line trunk 62. The central office switch 61 is I
An exchange having an SDN function, which is connected to a network terminating device 64 by a digital signal via a transmission line interface 63 and controls connection of a plurality of digital terminals via a user / network interface 65.

Up to eight digital terminals can be connected using the 2B channel of the ISDN signal.
Only two of them can be connected at the same time, and each digital terminal is connected to the other terminal via the exchange by the B channel signal at the speed of 64 Kbps. But now I
The terminals that can be connected to the SDN line are limited to those having the protocols of layers 1 to 3 developed for ISDN.

[0008]

There are two 64 Kbps communication B channels and one 16 Kbps control D channel in the ISDN line. Even now, there is a case where a specific terminal uses a single 64 Kbps B channel at a rate of 48 Kbps (video) + 16 Kbps (voice) to enable special services. In this case, there is a problem that it is impossible to communicate with a normal ISDN terminal.

Therefore, in the present invention, one 64 Kb is used as in the conventional case.
In order to solve the problem that only one digital terminal can be connected with ps B channel, 32Kb in 64Kbps
In the case of ps × 2 or 16 Kbps × 4, the exchange side converts these irregularly used channels into 64 Kbps, and conversely, installs a device that converts from 64 Kbps to 32 Kbps or 16 Kbps The purpose is to multiplex.

[0010]

FIG. 1 is a block diagram showing the principle of the present invention. In the figure, 1 is a central office switch, 2 is a line trunk, 3 is an analog subscriber circuit, 4 is an expansion compression converter,
Reference numeral 5 is a network terminator, 6 is a multiplexer A, 7 is a multiplexer B, 8 is an S / T point, and 9 is a U point.

U point 9 is a transmission line interface, and I
2B + D signal for SDN is transmitted / received, and S / T point 8
Is a user / network interface, and controls the connection between the network terminating device 5, the multiplexer A6 on the terminal side, and the multiplexer B7. It is assumed that one multiplexer A6 connects two 32 Kbps service terminals and the other multiplexer B7 connects a total of four 16 Kbps service terminals and analog telephone terminals.

In the central office switch 1, a line trunk 2 is connected to a network terminating device 5 via a transmission line interface U point 9, and an expansion compression converter 4 is 32 Kbps from the line trunk 2.
Signals and 16Kbps signals are expanded and compressed to 64Kbps signals,
The analog subscriber circuit 3 is connected to an analog telephone terminal.

[0013]

[Operation] FIG. 2 shows a combination of the usage methods of 64 Kbps B channel × 2. (A) One B channel has 32 Kbps service terminal x 1 and the other B channel has 16 Kbps service terminal x
When 1 is connected, (b) shows 32 Kbps for one B channel
When service terminal x 2 and 16 Kbps service terminal x 4 are connected to the other B channel, (c) is when analog telephone terminal x 4 is connected to one B channel and analog telephone terminal x 4 is connected to the other B channel. Indicates.

In the case of FIG. 2A, S of ISDN
32Kbps or 16 in the interface connected to the / T point
By assigning a compressed digital audio or video signal to Kbps, it is assigned to one of 64 Kbps, and the converter on the exchange side converts it between 16 Kbps or 32 Kbps and 64 Kbps. It becomes possible to communicate with analog telephone terminals.

In the case of FIG. 2B, S of ISDN
32Kbps or 16 in the interface connected to the / T point
64 Kb digital audio or video signal compressed to Kbps
If 32 Kbps is multiplexed on ps B channel, 2 lines are multiplexed, 16 Kbps is 4
After the main multiplexing, these exchanged 64 Kbps channels are converted into 32 Kbps to 64 Kbps and 16 Kbps to 64 Kbps, and communication with a normal ISDN terminal or analog telephone terminal becomes possible.

In the case of FIG. 2C, S of ISDN
In the analog / digital conversion and compression unit connected to the / T point, four analog telephones are multiplexed to form one 64Kbps B channel, which is then converted to a normal 64Kbps by the conversion device on the exchange side.
By converting to, it is possible to connect a maximum of eight analog telephone terminals with the two B channels of the ISDN line.

[0017]

FIG. 3 is a block diagram of a connection block diagram of the present invention.
Shown in. In the figure, 11 is a line control unit, 12 is a digital subscriber circuit (DLC), and 13 is an analog subscriber circuit (SL).
C), 14 is a digital trunk (DT), 15 is a network section, 16 is a network terminator, 17 is a data rate compatible interface section, 18 is a mobile telephone base station multiplexing section, and 19 is a data compression / expansion conversion section. .

The internal structure of the exchange is a digital subscriber circuit.
12 is connected to a network terminator 16 via a transmission line interface U point, is connected to an analog terminal by an analog subscriber trunk 13, is connected to a trunk line by a digital trunk 14, and is switched by a network unit 15. . The line control unit 11 has a data compression / expansion conversion unit 19, and controls the line connection between the data rate interface unit 17 and the mobile telephone base station multiplexing unit 18 connected to the S / T point via the network terminating device 16. I do.

The data rate interface unit 17 has 64
It has interface units corresponding to Kbps service terminals, 32 Kbps service terminals, 16 Kbps service terminals, and analog telephone terminals, and each terminal is multiplexed to the network terminating device 16 via the user / network interface unit (S / T point). Connected.
The mobile telephone base station multiplexer 18 wirelessly connects to the mobile unit, and
It is connected to the network terminator 16 via the / T point.

The signal rate of each terminal connected by the data rate compatible interface section 17 and the mobile telephone base station multiplexing section 18 is compressed and sent to the exchange side through the 64 Kbps B channel line. 64 Kbps compressed B on the exchange side
The data compression / expansion converter 19 converts the data rate of the channel, expands the channel to the original speed, and sends it to the network unit 15.

The data rate interface unit 17 includes
You can connect up to 2 terminals for 32Kbps service terminals, 4 terminals for 16Kbps service terminals, and 4 terminals for analog telephone terminals. The total speed of these terminals is 64Kb.
Connected to be ps. Therefore, it is possible to multiple-connect one 32 Kbps service terminal and 16 Kbps service terminals or 2 analog terminals in total.

A total of 144 Kbps of (2B + D) channels can be connected to one network terminating device 16, but by connecting two data rate interface units 17, 64 Kb
It is possible to connect 2 terminals for ps service terminals, 4 terminals for 32Kbps service terminals, 16Kbps service terminals or 8 terminals for analog terminals in combination. Also, as shown in the figure, one data rate interface unit 17 and one mobile telephone base station multiplexing unit 18 can be connected.

FIG. 4 shows an embodiment of a block diagram of a data rate interface unit. In the figure, 21 is a multiplexer, 22 is each interface unit, 23 is an S / T point interface unit, 24 is a protocol control unit, and 25 is a layer 1-3.
The control unit, 26 is a microprocessor. Multiplexer 21
Is connected to the network terminating device via the S / T point by the S / T point interface unit 23.

Each interface unit 22 has a 16 Kbps port for a 16 Kbps terminal, and 32 Kbps, 64 Kbps ports for 32 Kbps.
The terminal is connected to the analog terminal by an analog port. The channel signal compressed in each interface unit 22 is protocol-controlled in the protocol control unit 24 and the layers 1 to 3 control unit 25, and the S / T point interface unit
It is sent to the S / T point interface by 23.

FIG. 5 shows an embodiment of a frame structure for transmitting compressed data to a normal ISDN line. In the figure, a normal ISDN line (16 Kbps for control, 64 Kbps for communication)
X 2 channels) 1 frame is 2 bits, 125 μ
It consists of s control channel and 2 channels for communication of 8 bits and 125 μs. When compressed data is transmitted, if 16 Kbps is transmitted in one frame, 8 channel configuration is sent out for communication, and a combination of 16 Kbps and 32 Kbps. If combined, a 6-channel configuration is sent out for communication.

FIG. 6 shows an embodiment of a block diagram of a mobile telephone base station multiplexer. In the figure, 31 is a base station multiplexer, 32 is a transmission / reception amplifier, 33 is a transmission / reception unit, 34 is a common control unit, 35 is a test transmission / reception device, 37 is a multiplexing unit, and 38 is S.
/ T interface section, 39 indicates an Info control section / protocol control section / multiplex signal control section.

The figure shows an example of a base station having an S / T point interface. A 16 Kbps multiplexed signal is transmitted / received to / from a network terminating device by an S / T bus. Connection control with the exchange is performed for mobile units in the frequency area of the base station. 64Kbps ISDN
Up to four mobile units can be connected to the line corresponding to the transmitting / receiving unit.

Next, FIG. 7 shows an embodiment of a block diagram of the data compression / expansion converter. In the figure, 41 is a data compression / expansion conversion device, 42 is a selector section, and 43 is a compression PCM.
-PCM converter (16 Kbps ← → 64 Kbps), 44 is compressed PCM
-PCM converter (32 Kbps ← → 64 Kbps), 45 is compressed PCM
-PCM conversion unit (64 Kbps ← → 64 Kbps), 46 is an NW interface unit, and 47 is a control unit.

Compressed 16 Kb from LSW of line controller
Extended conversion of ps, 32Kbps and 64Kbps signals to 64Kbps
Return to W and conversely compress the 64 Kbps signal from LSW to 16
It has a data compression / expansion conversion function of compressing and converting to Kbps, 32 Kbps, and 64 Kbps and returning to LSW. Compressed PCM-PCM
The conversion unit must be provided for the codec format of the compressed data.

FIG. 8 shows an embodiment of a block diagram of the compression PCM-PCM converter. In the figure, 51 is a compressed PCM
-PCM conversion unit, 52 is an interface unit, 53 is an EC unit,
54 is a codec section, 55 is a codec transparent section, and 56 is an interface section. Compressed data is input / output to / from the interface unit 52, and is connected to a terminal in which 64 Kbps is compressed to 16 Kbps or the like. The interface unit 56 is an input / output unit for 64 Kbps data, and is connected to an analog terminal, an ISDN terminal or the like.

FIG. 9 shows a processing flowchart of the compression PCM-PCM conversion section. FIG. 9A shows the case of an incoming call.
(B) shows the case of making a call. In the case of the incoming call shown in FIG. 9A, (1) it is checked whether or not the channel at the S / T point is vacant, and if it is not vacant, a busy tone is transmitted. (2) If it is free, it refers to the control information of the compressed PCM of the terminal and notifies the conversion unit of the control information. (PCM and compressed PC
The connection information between Ms is TS of normal PCM by referring to the table.
To which TS of the PCM and the compressed PCM converter should be connected) (3) Connect the compressed PCM-PCM converter. (4) Connect the line.

In the case of the call shown in FIG. 9B, (11) it is checked whether or not the channel is idle, and if it is not idle, a busy tone is transmitted. (12) Notify the data compression / expansion converter of control information on the control channel. (Information such as what bit in which TS should be fetched) (13) Connect the compression PCM-PCM converter. (Information such as which conversion unit the compressed PCM should be connected to) (14) Line connection is made.

[0033]

According to the present invention, a digital signal (voice or video) from the terminal side compressed to 32 Kbps or 16 Kbps is expanded / compressed in a device on the exchange side so that a normal ISDN terminal or analog telephone terminal can be obtained. Communication becomes possible.

Also, by making multiple use of the resources of the 2B-channel of the ISDN line, effective use of the channel becomes possible. It should be noted that the current ISDN device remains as it is, and this service can be provided only by the additional device.

[Brief description of drawings]

FIG. 1 is a block diagram of the principle of the present invention.

FIG. 2 Combination of usage methods of B channel × 2

FIG. 3 is an example of a connection configuration block diagram of the present invention.

FIG. 4 is an example of a block diagram of a data rate interface unit.

FIG. 5: Example of frame configuration

FIG. 6 is an embodiment of a block diagram of a mobile telephone base station multiplexer.

FIG. 7 is an example of a block configuration diagram of a data compression / expansion conversion unit.

FIG. 8 is an example of a block configuration diagram of a compression PCM-PCM conversion unit.

FIG. 9 is a processing flowchart of a compression PCM-PCM conversion unit.

FIG. 10 is a connection configuration diagram of a conventional ISDN terminal.

[Explanation of symbols]

 1,61 Switch for office 2,62 Line trunk 3,13 Analog subscriber circuit 4 Expanded compression converter 5,16,64 Network termination device 6,7,21 Multiplexer 8,65 S / T point 9,63 U Point 11 Line control unit 12 Digital subscriber circuit 14 Digital trunk 15 Network unit 17 Data rate compatible interface unit 18 Mobile telephone base station multiplexing unit 19 Data compression / expansion conversion unit 22 Each interface unit 23, 38 S / T point interface unit 24 Protocol control unit 25 Layers 1 to 3 control unit 26 Microprocessor 31 Base station multiplexer 32 Transmission / reception amplifier 33 Transmitter / receiver 34 Common controller 35 Test transmitter / receiver 37 Multiplexer 39 Info controller / protocol controller / multiplexer Signal control unit 41 Data compression / expansion conversion device 42 Selector unit 43, 44, 45 Compressed PCM-PCM conversion unit 46 NW interface unit 47 Control unit 51 Compressed PCM-PCM Section 52 56 Interface unit 53 EC 54 CODEC 55 codec transmitting portions 66 and 67 a digital terminal

Claims (2)

[Claims] 1. An exchange (1) for connecting a digital terminal using an ISDN digital line, a line trunk (2) for connecting to a network terminating device (5) through a transmission line, and a line trunk (2) An expansion compression conversion unit (4) is provided for expanding and converting the compression-encoded digital signal to the original digital signal, receiving the compression-encoded digital signal from the network terminating device, and transmitting it to the line trunk (2). One or a plurality of service terminals for transmitting and receiving the compression-coded digital signal are connected to the network terminating device (5) through a multiplexing device (6, 7), and ISDN for ISDN is provided through the transmission path. By converting the compression-coded digital signal transmitted / received through the communication channel into the original digital signal, an analog telephone terminal connected to the exchange (1) or a normal telephone terminal. A method for applying a digital terminal using an ISDN line, characterized by communicating with an ISDN terminal. 2. The multiplexer (6, 7) is provided with a compression expansion unit for mutually converting an analog voice signal and a compression-encoded digital signal, and the multiplexer (6, 7) is an analog telephone terminal. The method for applying a digital terminal using an ISDN line according to claim 1, characterized in that it is also accommodated.