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PCM120 is one module, designed for large volume, with multi-E1 ports. 1&16 sets of MUX card can be plugged. With 16 MUX, PCM120 works as a completely cross-connect equipment. Usually , we use 1&2 MUX for 4&8 E1 ports. PCM120 distributes signals to multiple E1 directions. With high density as well as high reliability, PCM120 can transfer 210 loops two-channel analytic audio signal at its maximal rate. Plugin board is hot swapped. With LED alarm, each board is supervised conviniently. PCM120 works smoothly with other module of PCM.

With the NM software, E1 adopts 1+1 protection. It will switch automatically to another E1, when meets problems.


PCM 120 contains 18 card slots. Both side card slots are power plugin. Commonly, one MUX board is needed, or 1+1 for protection, which lieds the 9th/10th card slot. The other 14 slots are for the service card, such as 2 wire voice channel, 2/4 E&M channel, V.11/V.24 channel. According to the amount of MUX board, PCM120 multiplexes 4-8 E1 to transfer.

PCM120 Signal Processing Slot List
Module Introduction
ZN787 -48V DC power supply card, ring module integrated
MUX120 4E1 MUX card, 4 channels V.24 extensible
ZN751An FXS, 5/6/10 channels optional, 4ST-BUS
ZN752An FXO, 5/6/10 channels optional, 4ST-BUS
ZN756An 2/4 E&M, 5/6/10 channles optional, 4ST-BUS
ZN747An V.11/V.24 data card, 5/6 channels optional, 4ST-BUS


Frame Parameter

The framework of PCM120 is steel. 19inch external width, 6U height, 30cm length.

This equipment can be screwed through mounting hole to 19 inch cabinet.


Port Physical Parameter

Name Description
E1 port BNC coaxial connector
extension card port X100 socket(64 pins) per card
NM port DB9(socket)

Port Electrical Parameter

Technical features of PCM120 meets ITU-T G.703、G.711、G.712、G.713、G.714、G.732.

System Features

Transmission technique: PCM
Group Interface: E1
Gross bit rate: 2.048Mbit/s±50ppm
Sampling Frequency: 8KHz
Frame Time Slot Amount: 32
Channel Amount: 30
Bit Rate of Time Slot: 64Kbit/s
Signalling Signal: TS16
compliant to ITU-T REC\G.704
Frame Alignment Signal: TS0

2Mbit/s Interface(E1)

Transmission Type: HDB3
Transmission Rate: 2048Kbit/s
Permissible Deviation: ±5×10E-5
Impedance at E1 Interface: 75Ω/120Ω
E1 Signal Amplitude: 2.37V/3V


Capacity: 5/6/10
Standard Referred to: ITU-T\REC\Q.522
Frequency Range: 0.3-3.4KHz
Idle Channel Noise: < -65dBm0
Cross Talk: < -65dBm0
Relative Level Transmitted at F2an:
                  +3,0,-3dBr adjustable
Relative Level Received at F2ab:
                  +3,0,-3dBr adjustable
Max Loop Impedance: 2.4KΩ
Loop Feeding:
Loop Current: 22mA∼28mA
Ringing Generator Voltage:
                  75V(full load≥50V)
Ringing Frequency: 25Hz±10%


Capacity: 5/6/10
Standard Referred to: ITU-T\REC\Q.522
Frequency Range: 0.3∼3.4KHz
Idle Channel Noise: < -65dBm0
Cross Talk: < -65dBm0
Relative Level F2an: 0dBr
Relatvie Level F2ab: -3dBr
Loop Resistance: 470Ω
Audio Impedance: compound
Ring Current Detection Level:35V∼100V
Receive Ringing Frequency: 16Hz∼66Hz

2/4 wire E&M

Capacity: 5/6/10
Standard Referred to: ITU-T\REC\G.714
Signaling Mode: E&M
Audio Impedance: 600Ω
Transmission Relative Level at F2in:
-17.4∼+7dBr adjustable, 0 dBr initially
Receiving Relative Level at F2out:
-17∼+7dBr adjustable, 0 dBra initially

Power Supply and Operation Environment

Input Voltage Range: -36V∼72V DC
Maximum Output Power: < 20W
Performance Temperature: 0℃∼+40℃
Operation Temperature: -10℃∼+45℃
Storage Temperature: -40℃∼+60℃
Performance Humidity: 10%∼90%(+35℃)
Operation Humidity: 5%∼95%(+35℃)

Data Interface Card

Capacity: 5/6
Asynchronous Data Channel V.24/RS232
Logic Level: 0=+10V,1=-10V
Transmission Rate: 0-19.2kbit/s
Sampling Rate: 64KHz
Interface Static Protection: Available
Interface Protection Voltage: ±10V
Asynchronous V.11/RS422/485
Signal Line Amount: 4
Input Detection Capability:
                  :Ua-Ub> 0.07V
Output Signal Level:
                  Ua-Ub=5V(zero loaded)
Transmission Rate: 0∼19.2Kbit/s
Synchronous V.35
Clock Interface Type: DCE

Point to Point

One to Multipoint Mode

Ring Mode



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