JPH033595A - Digital communication network interface equipment - Google Patents

Abstract

PURPOSE:To eliminate the need for a speed conversion circuit between inter and outer data, a phase absorbing circuit and a subsequent synchronizing circuit by sending a digital data in the inside of a digital communication equipment to an external digital communication network and converting the digital signal into an analog signal once on its way when the signal is received from a digital communication network. CONSTITUTION:CODECs 43a, 43b read a voice data (PCM code) at a speed of 2Mbps according to a basic clock PHCLK from a designated time slot and convert it into an analog voice signal. The analog voice signal is inputted to CODECs 49a, 49b through level adjustment amplifiers 47a, 47b. The CODECs 49a, 49b convert the analog voice signal again into the PCM code synchronously with the clock from an ISDN given through an S interface circuit 23 and output to the S interface circuit 23 at a speed of 64kbps. Thus, it is not required to apply speed matching and phase matching of digital data at both sides directly and the constitution is simplified and the cost is reduced.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides communication terminals such as telephones to an integrated service digital network (ISDN).
emces Digital Network)
The present invention relates to a digital communication network interface device that is installed in a digital key telephone main device, digital data, etc., in order to connect to a digital communication network such as a digital button telephone main device, digital data, etc.

(Prior Art) In recent years, in telephone communication networks, a digital communication network called an integrated service digital network (hereinafter referred to as 15DN) has been put into operation in place of the existing analog telephone network. In order to operate this L5DN, it is necessary to interoperate with the existing network, and terminals for L5DN are expensive. Convert your existing terminal to 5D
A method of connecting to N is adopted.

FIG. 2 shows a general system configuration of this type of system.

In the figure, a terminal interface unit 5 for connecting an extension terminal such as a standard telephone 3 and an I5DN interface unit for connecting an I5DN 7 as an outside line are included in a digital key telephone main device 1 (or digital PBX). 9 has been implemented. Both interface units 5.9 are connected to the control unit 15 via a control data highway 11 and a speech highway 13. In this way, voice communication is possible between the standard telephone 3 and the I5DN 7 through the digital key telephone main device 1. That is, the digital key telephone main device 1 plays the role of a terminal adapter for connecting the standard telephone 3 to the 15DN7.

In this way, the digital button telephone main device 1 and the digital PBX internally process communication data in the state of digital data.
When a terminal is connected to a digital communication network such as L5DN through a communication device such as L5DN, voice data is processed at an extremely high speed in order to multiplex a large number of channels within such communication device. I/O speeds are much slower. For example, in the digital key telephone main device 1, the speech highway 13 is generally 2 Mb.
Voice data is transmitted at a speed of ps, but l5DN
7's audio input/output speed is 64 Kbps. Therefore, it is necessary to compensate for such data rate differences.

For this reason, the conventional 15DN interface unit 9 has a configuration as shown in FIG. In the figure, 64/2M speed conversion circuit 17a for the first audio channel and 64/2M speed conversion circuit 17a for the second audio channel.
The M speed conversion circuit 17b is connected to the speech highway 13. These speed conversion circuits 17a and 17b are
Each designated time slot of the speech highway 13 is accessed from the time slot assigner 19.

2Mb read from two specified timeslots
The ps audio data is speed-converted to 64 Kbps by speed converters 17a and 17b, respectively, and then input to elastic store memories 21a and 21b for absorbing phase differences. The elastic store memories 21a and 21b output audio data to the S interface circuit 23 in synchronization with the clock provided from the 15DN7 through the S interface circuit 23. S interface circuit 23
is a circuit for accessing the subscriber interface (referred to as 8 points) 22 of the l5DN7, and converts the 64 kbps audio data from the elastic store memory 21a121b into a predetermined format and sends it to the two audio channels of the l5DN7. Further, this S interface circuit 23 converts control data sent from the control processor 24 in the control unit 15 through the data highway 11 and the relay microprocessor 25 into a predetermined format and sends it to the control data channel of the 15DN7. . On the other hand, the voice data and control data sent from the 15DN7 are sent to the speech highway 13 and the control processor 24 through the reverse route to the above.

The clock of l5DN7 is also the clock of S interface circuit 2.
3 to the slave synchronization circuit 27. The slave synchronization circuit 27 generates a master clock DTCLK (4 MHz) slave-synchronized with the clock of 15DN7. This dependent synchronous clock DTCLK is sent to two clock generation circuits within the control unit 15. The clock generation circuit 29 is designed to select either the free-running clock from the internal oscillator 31 or the dependent synchronous clock DTCLK. In this case, it selects the dependent synchronous clock DTCLK and generates the basic clock (2 MHz) based on this. ) and a frame synchronization signal (8kHz). The data processing timing in the speech highway 13, time switch 33, etc. is determined by the basic clock and frame synchronization signal generated based on the slave synchronization clock in this way.

(Problem to be solved by the invention) As mentioned above, digital button telephone main equipment and digital
A conventional digital communication network interface unit installed in a digital communication device such as BX has a speed conversion circuit and a memory for absorbing phase difference in order to compensate for the difference in data speed and phase shift between the internal communication device and the external communication network. In addition, a circuit for slave synchronizing the internal clock to an external communication network is also required. Therefore, the conventional method has the disadvantage of having a complicated and large-scale circuit configuration and being expensive.

Therefore, an object of the present invention is to provide a digital communication network interface device that has a simple configuration and is inexpensive.

[Structure of the invention]

(Means for Solving the Problems) The present invention is provided in a digital communication device that internally processes communication data in the state of digital data, and provides communication between this communication device and a digital communication network having a different data speed. a first conversion means that operates in synchronization with the data rate inside the communication device and performs mutual conversion between digital data and analog signals in the communication device; a second conversion means operating in synchronization with the data rate of the network and for interconverting the analog signal to digital data within the digital communication network.

Furthermore, the present invention provides a digital communication network interface device having, in addition to the above configuration, means for adjusting the level of an analog signal.

(Function) According to the above configuration, the digital data inside the digital communication device is once converted to an analog signal, and then converted to digital data at a speed synchronized with the external digital communication network and sent to the external communication network. . Further, digital data from an external communication network is once converted into an analog signal, and then converted into digital data at a data rate within the communication device. In this way, since the communication data is converted into an analog signal in the middle, there is no need to directly match the speed or phase of the digital data on both sides. Furthermore, since the level adjustment of communication data can be performed when the signal is in an analog signal state, the degree of freedom in the amount of adjustment is greater than with a digital pad.

(Example) Examples will be explained below.

FIG. 1 shows the configuration of an interface unit for ISDN according to an embodiment of the present invention. It should be noted that elements having the same configuration as the conventional one are given the same reference numerals as the corresponding elements in FIG.

The I5DN interface unit 41 is implemented as an outside line interface unit in the digital key telephone main unit and is connected to the control unit 43 via the control data highway 11 and the speech highway 13. Although not shown, a terminal interface unit for connecting a terminal such as a standard telephone is also implemented in this main device and is connected to the control unit 43 via the control data highway 11 and the speech highway 13, so that the terminal Voice calls are now possible between 15DN and 15DN. Note that the parts not shown in the drawings, such as the terminal interface unit, may have the same configuration as that of a conventional digital key telephone main unit.

The basic interface of ISDN consists of two voice channels (64 kbps each) and one control data channel (16 kbps), which are time-division multiplexed and whose frame frequency is 8 kHz. The 15DN interface unit 41 is configured in accordance with such 15DN interface specifications.

That is, the codec 43a for the first audio channel and the codec 43b for the second audio channel are connected to the speech highway 13, and they are connected to the time slot of the speech highway 13 designated by the time slot assigner 45. to access. In the speech highway 13, 32 communication channels (time slots) are time-division multiplexed according to a 2 MHz basic clock PHCLK. Codec 43a.

43b is the basic clock P from the designated time slot.
Audio data (PC
M code) and converts it into an analog audio signal. This analog audio signal is sent to the level adjustment amplifier 47a.
, 47b and is input to codecs 49a and 49b. The codecs 49a and 49b convert the analog audio signal into a PCM code again in synchronization with the tarock from the 15DN provided through the S interface circuit 23, and output it to the S interface circuit 23 at a speed of 64 kbps.

The S interface circuit 23 has the same configuration as the conventional one,
Tri-level AMI for electrical interface with l5DN
It includes an encoding/complexing circuit, a circuit for separating and multiplexing audio and control channels, and a control circuit for each channel. This S interface circuit 23 is connected to the subscriber side interface (S point) 22 of the l5DN, and converts the audio data from the codecs 49a and 49b to the l5D.
Send to the N audio channel.

In addition, the S interface circuit 23 separates the audio data sent from the 15DN into 64K channels for each channel.
It is sent to codec 49a149b at a speed of bps. The codecs 49a and 49b receive and receive audio data in synchronization with the clock from the 15DN, and convert it into an analog audio signal. This analog audio signal is sent to a level adjustment amplifier 51a.

The signal is input to codecs 43a and 43b through 51b. The codecs 43a and 43b convert the analog audio signal into a PCM code in synchronization with the basic clock PHCLK of the speech highway 13, and transmit it to a designated time slot of the speech highway 13 at a speed of 2 Mbps.

The audio level is adjusted using level adjustment amplifiers 47a, 47b, and 51a when the signal is an analog signal.

51b. These level adjustment amplifiers 4
7a, 47b, 51a, and 51b are placed under the control of a control processor 24 within the control unit 15. Level adjustment in an analog signal state has the advantage that the degree of freedom in adjustment is greater than in the digital pad method for digital data.

Regarding the control data, it is applied from the control processor 24 in the control unit 15 to the S interface circuit 23 via the data highway 11 and the relay microprocessor 25, and then sent to the control data channel of the 15DN. In addition, control data is sent from the 15DN to the control processor 24 through a route opposite to this. Call connection processing and the like are performed in accordance with control data given to the control processor 24 from this I5DN.

A clock generation circuit 29 in the control unit 15 generates a basic clock and a frame synchronization signal based on the free-running clock from the internal oscillator 31, and generates a basic clock and a frame synchronization signal.
and the time switch 33, etc.

〔Effect of the invention〕

As explained above, according to the present invention, when digital data inside a digital communication device is transmitted to an external digital communication network and received from the digital communication network, it is once converted into an analog signal in the middle. Since a speed conversion circuit between internal and external data, a phase absorption circuit, and a dependent synchronization circuit are not required, the configuration becomes simple and inexpensive, and level adjustment with a high degree of freedom is possible at the analog signal stage.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an l5DN interface unit according to an embodiment of the present invention, and Fig. 2 shows a general system configuration when a standard telephone is connected to an l5DN using a digital key telephone main device. A block diagram showing,
FIG. 3 is a block diagram showing the configuration of a conventional 15DN interface unit. DESCRIPTION OF SYMBOLS 1... Digital button telephone main device, 3... Standard telephone, 5... Terminal interface unit, 7... Integrated Service Digital Network (ISDN), 11... Control data highway, 13... Speech highway, 15
...Control unit, 22...15DN subscriber interface (S point), 23...S interface circuit, 41...15DN interface unit, 43
... Codec, 47.51 ... Level adjustment amplifier, 49 ... Codec.

Claims (1)

[Scope of Claims] 1. Data communication between a digital communication network provided in a digital communication device that internally processes communication data in the form of digital data, and having a data rate different from that inside the communication device, and the communication device. a first conversion means that operates in synchronization with a data rate within the communication device and performs mutual conversion between digital data and analog signals in the communication device; and a second conversion means operating synchronously with the data rate of the network for interconverting between said analog signal and digital data in said digital communication network. 2. The apparatus of claim 1 further comprising means for adjusting the level of said analog signal.