KR100221306B1 - A t1/e1 interfacing apparatus of a digital exchange - Google Patents

Abstract

The present invention relates to a T1 / E1 matching device for connecting between the communication processing system and the public telephone network in an E1 or T1 station relay system in a communication processing system for connecting a public telephone network and a packet network. The apparatus of the present invention is connected to the public telephone network E1 or T1 line matching unit 41 for processing line coding and decoding; A clock extracting unit (44) for extracting a clock from the received data of the line matching unit; A network synchronizer 45 which is composed of a PLL circuit for oscillating a signal of a predetermined frequency and receives 4KHz in synchronization with the clock extracted from the clock extractor and synchronizes the oscillated clock with the received clock; A divider unit 46 which divides a clock output from the network synchronizer unit 45 according to the E1 / T1 selection signal input from the line matching unit to provide a synchronized clock of a predetermined frequency; A clock converter 47 which receives the synchronized E1 clock from the division unit and outputs the synchronized T1 clock; A frame reproducing unit (42) for rearranging the data received from the line matching unit (41) according to the T1 clock output by the clock converting unit (47) to reproduce the frame; A digital switch 43 for exchanging specific timeslots in the T1 / E1 frame structure according to the control signal; And a microprocessor 48 for generating a control signal for controlling the operation of the digital switch by executing a predetermined program.

Description

A T1 / E1 interfacing apparatus of a digital exchange

The present invention relates to a T1 / E1 matching device of a digital electronic switching system, and in particular, an apparatus for synchronizing T1 and E1 clocks to process T1 or E1 in the same block in a communication processing system for connecting a public telephone network and a packet network. It is about.

In general, a public telephone network is a communication network for transmitting voice signals to other subscribers in a network by performing circuit switching according to call requests of telephone subscribers, and a packet switching network is a communication network for transmitting digital data between computers through packet switching. Although these networks tend to be integrated with each other as the B-ISDN is promoted, they are still composed of individual networks, so the procedures for exchanging services between networks have been very complicated.

Almost all households and companies are subscribed to the public telephone network and are used most widely, but the service is mainly voice-based telephone service. However, as the information society progresses, data transmission between computers is widely required, and various information providers are on the rise and the demand for access to packet networks is rapidly increasing. Therefore, the service of the type connected to the packet switching network has been increased by using the telephone line used in the general home, and for this purpose, a communication processing system has been introduced to the connection between the public telephone network and the packet network as shown in FIG.

The communication processing system is connected to the public telephone network in the form of a T1 / E1 trunk, and the packet network is connected according to the X.25 protocol. A conventional trunk matching device connecting the public telephone network and the communication processing system is connected to the type of trunk to be input. Therefore, the board is to be used. In other words, when processing the T1 or E1 in the conventional trunk matching device, since the clocks of T1 and E1 are different, some circuit options or board types are changed so that the clock can be provided according to the method used. It was uncomfortable.

Accordingly, the present invention has been made to solve the above problems, and even in the case of a digital transmission system in which the T1 or E1 can be processed in the same circuit configuration by providing a synchronized clock even when the trunk transmission method is different. The purpose is to provide a trunk matching device.

In order to achieve the above object, the apparatus of the present invention, in the communication processing system for connecting the public telephone network and the packet network to a trunk matching device for connecting between the communication processing system and the public telephone network in an E1 or T1 station relay method. A line matching unit connected to the public telephone network with E1 or T1 to process line coding and decoding; A clock extracting unit for extracting a clock from the received data of the line matching unit; A network synchronizer configured of a PLL circuit for oscillating a signal having a predetermined frequency and receiving 4KHz synchronized with the clock extracted from the clock extractor to synchronize the oscillated clock with the received clock; A divider for dividing a clock output from the network synchronizer according to the E1 / T1 selection signal input from the line matching unit to provide a synchronized clock of a predetermined frequency; A clock converter which receives the synchronized E1 clock from the division unit and outputs the synchronized T1 clock; A frame reproducing unit for rearranging the data received from the line matching unit 41 and reproducing the frame according to the T1 clock output by the clock converting unit; A digital switch for exchanging specific timeslots in a T1 / E1 frame structure according to a control signal; And a microprocessor for generating a control signal for controlling the operation of the digital switch by executing a predetermined program.

1 is a view schematically showing a coupling form between a public telephone network and a packet network;

2 is a block diagram showing an internal configuration of the communication processing system shown in FIG. 1;

Figure 3 is a block diagram showing a T1 / E1 matching device of the digital electron exchanger according to the present invention.

* Explanation of symbols for main parts of the drawings

12: public telephone network (PSTN) 14: communication processing system

16: packet network 20-1 to 20-n: communication processing device

22: trunk matching unit 24: switching unit

26: subscriber registration unit 27: main switch

41: line matching section 42: frame playback section

43: digital switch 44: clock discharge unit

45: network controller 46: divider

47: clock conversion unit

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

1 is a diagram schematically illustrating a coupling form between a public telephone network and a packet network. In FIG. 1, a plurality of telephones, personal computers, hightel terminals, etc. are connected to a public telephone network 12 through a telephone line, and an exchange node of the public telephone network 12 and a communication processing system 14 are connected by a trunk connection. The communication processing system 14 and the packet network 16 are connected by X.25. Several types of information providers are connected to the packet network. At this time, personal computer and public telephone network are connected by modem.

Therefore, in order to connect to a hightel using a personal computer or a hightel terminal connected to a public telephone network, the call is connected to a predetermined hightel number and then communicated. At this time, the connection can be made more efficiently through the communication processing system 16. .

Here, the communication processing system 14 is called ICPS (Information Communication Processing System). In the past, when the DB of the packet network used the 01410 subscriber for a long time using the telephone network, the telephone network was overloaded. By installing (ICPS) in the middle of the network, traffic can be controlled and the desired menu can be accessed directly, saving time when searching for information. In addition, by extracting and recording the user's outgoing telephone number, the user system can be improved through simple access, and it helps subscribers to access the distributed database. It acts as a node processor that can be linked and form a nationwide database network.

This communication processing system is largely composed of communication processing apparatuses 20-1 to 20-n and a regional management apparatus (not shown). The communication processing apparatuses 20-1 to 20-n are connected to a public telephone network 12. It has T1 / E1 station-to-station connection function, and connects network and packet network by X.25 connection of packet network and 56Kbps, and provides high speed 14.4Kbps dial-up modem connection function of up to 96 lines per communication system. do. In addition, there is an outgoing call identification and storage function for billing, and it supports VT-100 / 220 data terminal identification and videotex mode terminals. Also, there is a function of providing Korean menu, weak sign, and billing data transmission to local management device.

As shown in FIG. 2, the communication processing apparatus includes a trunk matching unit 22, a switching unit 24, and a subscriber matching unit 26.

The trunk matching unit 22 is connected to the public telephone network 12 by 4T1 or 3E1, and extracts a clock and provides it to another unit of the communication processing device. Connect. The switching unit 24 processes the switching function, and the subscriber matching unit 26 is connected to the main switch 27 side through a modem and connected to the packet network.

On the other hand, the regional management device manages up to 32 communication processing devices, and there are detailed billing processing functions for all access calls, DB management function in IP, DB usage guide and billing function, and weak sign registration function by Korean menu. . The local management device is composed of communication processing device connection part, billing recorder, information guide device, etc., and host system is structured to manage communication processing device by remotely accessing HiNet-P network by duplexing Tycom to LAN.

Figure 3 is a block diagram showing a T1 / E1 matching device of the digital electron exchanger according to the present invention.

As shown in FIG. 3, the T1 / E1 matching device according to the present invention includes a line matching unit 41, a frame reproducing unit 42, a digital switch 43, a clock extracting unit 44, and a network synchronizer 45. PLL), divider 46, clock converter 47, microprocessor 48, and the like.

The line matching unit 41 is matched with the public telephone network 12 and the E1 station relay method or the T1 station relay method. At this time, E1 has 32 PCM channels multiplexed to have a transmission rate of 2.048 Mbps, and T1 has 24 PCM channels multiplexed at 1.544 Mbps. The line matching unit 41 processes line coding and decoding to transfer data through a transmission line.

The clock extractor 44 extracts a clock from data received through the line matcher 301. At this time, since the T1 or E1 signal may be received in the trunk line according to the present invention, in the case of T1, the clock extractor 44 extracts a clock of 1.544 MHz from the timing of the received data, and in the case of E1, 2.048. Extract MHz.

The network synchronizer 45 is composed of a PLL circuit oscillating 16.384 MHz, receives 4KHz synchronized with the clock extracted from the clock extractor 44, and synchronizes the internally oscillated 16.384 MHz signal with the received clock. 45 divides the clock output from the network synchronizer 45 according to the E1 / T1 selection signal input from the line matching unit 41 to provide synchronized clocks of 4 MHz, 2.048 MHz, 8 KHz, and 4 KHz.

The clock converter 47 receives a synchronized 2.048 MHz (P2.048 MHz) and outputs a synchronized 1.544 MHz (P1.544 MHz).

The frame reproducing unit 42 rearranges the data received from the line matching unit 41 according to the synchronous clock output from the clock converting unit 47 to reproduce the frame, and the digital switch 43 has a T1 / E1 frame structure. Switch the timeslot at, and switch to E1 (32 channels) when it is input in T1 (24 channels). Here, the digital switch 43 may be implemented by MT8980D and the like of Mittel.

The microprocessor 48 performs a program to control the operation of the digital switch 43.

Next, the operation of the apparatus according to the present invention configured as described above will be described in detail.

First, the structure of the T1 and E1 frames used in the present invention will be briefly described as follows.

In T1 frame, 12 PCM channels (DS0: 64Kbps) are multiplexed together with the frame bits, which has a speed of 1.544 Mbps, and 12 frames are multiplexed to form a multiframe (or superframe). The eighth bit is called an 'A' bit in each channel, and the eighth bit is called a 'B' bit in each channel of the 12th frame. And the signaling of each channel is made by these "A, B" bits, for example, A bit is 0 for on-hook and 1 is for off-hook. Bit 0 indicates no ringing, and bit 1 indicates ringing. The line code in T1 is AMI or B8ZS.

The E1 frame has 32 PCM channels (64 Kbps) multiplexed at 2.048 Mbps, 30 channels for subscriber data transmission, and 2 channels for signaling and frame synchronization. That is, 16 E1 frames are multiplexed to form a multi-frame, and channel 0 (time slot 0) of even frames forming the multi-frame is used for frame synchronization bits, and channel 0 of odd frames is used for remote alarm and national bits. Used. The 16th channel (time slot 16) of the first frame forming the multi-frame is used for the multi-frame sync bit, and the 16th channel of the second to sixteenth frames is used for signaling of each channel (30 channel). HDB3 is used as the line code of the T1 frame.

In FIG. 3, when the public telephone network is connected to the E1 trunk system, the line matching unit 41 is connected to the exchange node (trunk side) of the public telephone network through the E1 line. At this time, the data transmitted through the E1 line is encoded and transmitted by the HDB3 method, and the data received by being encoded by the HDB3 method is decoded to convert the binary signal. The clock extractor 44 extracts the clock for the synchronizer from the data received through the line, and synchronizes the internally oscillated signal with the extracted clock in the synchronizer PLL 45 and the PLL in the divider 46. The oscillation clock output by (45) is divided according to the T1 / E1 selection signal input from the line matching section to provide various clocks (4 MHz, 2.048 MHz, 8 KHz, 4 KHz) required by the system.

The frame reproducing unit 42 forms an E1 frame for transmission or rearranges the received data by rearranging the received data according to a synchronized clock output by the clock converting unit. The microprocessor 48 controls the digital switch 43 by executing a stored program, and thus the digital switch 43 performs a switching operation.

As described above, the T1 / E1 matching device according to the present invention can match T1 or E1 with the trunk side, but can process T1 or E1 in a single circuit configuration by providing the converted clock according to the selection signal. The circuit configuration is simplified, and the manufacturing cost can be reduced.

Claims (1)

A trunk matching device for connecting between a public telephone network and a packet network through an E1 or T1 station relay system in a communication processing system for connecting a public telephone network with a packet network, wherein the trunk matching device is connected to the public telephone network by E1 or T1 to perform line coding. And a line matching unit 41 for processing decoding, a clock extracting unit 44 for extracting a clock from the received data of the line matching unit, and a PLL circuit for oscillating a signal having a predetermined frequency, which is extracted from the clock extracting unit. Receives 4KHz synchronized with the clock and synchronizes the oscillated clock to the received clock, and divides the clock output from the synchronizer 45 according to the E1 / T1 selection signal input from the line matching unit. A divider unit 46 for providing a synchronized clock of frequency, a clock converter 47 for receiving a synchronized E1 clock from the divider unit and outputting a synchronized T1 clock; The frame reproducing unit 42 rearranges the data received from the line matching unit 41 according to the T1 clock outputted by the clock converting unit 47 to reproduce the frame, and specifies the T1 / E1 frame structure according to the control signal. T1 / E1 of the digital electronic switch, characterized in that it comprises a digital switch (43) for exchanging timeslots and a microprocessor (48) for performing a predetermined program to generate a control signal for controlling the operation of the digital switch. Matching device.

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