PCM equipment

The configuration of PCM equipment is basically the same. This book uses Huawei FA16 equipment as an example. PCM equipment and its frame layout are shown in Figure 1

PCM equipment
Figure 1 PCM equipment and its frame layout

FA16 equipment includes cabinet, power supply, environmental monitoring box, alarm box, fan, PV8 main control box, RSP expansion box and other parts. Main control board, PCM power board, PCM FXO voice interface (CDI) board, PCM2/line E&M (ATI) interface board, PCM V.24 data interface board (SRX) board, etc. See Figure 2 (a: main control board, b: PCM power supply board PWX board, c: PCM CDI board FXO voice interface board, d: PCM ATI board 2/4-wire E&M interface, e: PCM SRX board V.24 data interface plate)

PCM equipment
Figure 2 Schematic diagram of PCM typical interface board
  1. Main control board (PV8)
    It has a 2k×2k cross matrix, provides 64kbit/s-based crossover capability; provides V5 protocol processing and internal HGRP protocol processing; responsible for phase-locking the clock from the E1 interface and distributing it to the subscriber unit. Each PV8 board provides 40 HWs, 32 of which are used to connect to the expansion user frame, and the other 8 are used to connect to the users of the PV8 frame; the main processor: the main PV8 board connects the user boards, The test board and the spare PV8 board are monitored; each PV8 board provides 8 E1 interfaces, and the two PV8 boards have a total of 16 E1 interfaces, which work in a load sharing manner. In this way, the PV8 main control frame can access 16 E1 links.
  2. Power board (PWX board)
    There are 2 PWX boards in the PV8-10 main control box, and each PWX board occupies 2 slots. Two PWX boards are hot backup for each other, and one of them can work normally to supply power to the entire frame. PWX board input is -48V DC input, output is DC +5V/30A, -5V/10A; PWX board output ring current is AC 75V/400mA.
  3. FXS voice interface (ASL board)
    ASL is a voice user interface board, which completes the FXS (outer circle exchange user side interface) function, and is generally used to connect to user phones. Analog user board, providing 16 analog user ports. It has seven major functions of BORSCHT, including: B—feeding; 0-overvoltage protection; R—ringing control; S—loop monitoring; C—coding and decoding; H—hybrid circuit; T—testing.
  4. FXO voice interface board (CDI board)
    The voice user interface board is used to connect to the switch side to complete the function of FXO. Directly dial into the user interface board to realize the transparent transmission of analog user ports, provide 16 analog user ports, compatible with the ASL board slot, and use the same cable as the ASL.
    As an FXO interface, it can be used in conjunction with FXS to realize the analog access of the access network POTS (plain old telephone service) users to the local exchange (LE). The FXS interface is provided by the ASL board.
  5. 2/4 wire E&M interface (ATI board)
    Simulate user interface board, provide 2/4 line E&M interface service. ATI (analog trunk interface, analog trunk interface) board is a 2/4-wire E&M interface board for FA16 access network system. The ATI board is compatible with the user board slot and can provide 6 2/4-wire E&M interfaces.

6.V.24 data interface board (SRX sub-rate board)
The SRX sub-rate board provides data interface services. Provide RS-232/V.24 data interface services. Its functions are as follows: The H301SRX board is a sub-rate data interface board of the FA16 access network system; it can provide 5 sub-rate data ports with adjustable rates, respectively 2.4, 4.8, 9.6, 19.2kbit/s and 48kbit/s, 5 ports share a 64kbit/s time slot; H301SRX board is compatible with common user board slots; H301SRX data user board provides 5 V.24 synchronous sub-rate ports. The port rate can be set to 2.4, 4.8, 9.6, 19.2kbit/s and 48kbit/s in the data control console of the terminal system of the access network.