4
X
E1/G.703 P
LESIOCHRONOUS
M
ULTIPLEXER
O
PERATING
M
ANUAL
IOA77-1F
16
May 2007
4.4 E1/G.703 linear signal connection
4.4.1 TM-77 and MD-77
E1/G.703 interface input and output signals of
TM-77 and MD-77
devices are transmitted
via two screened symmetric cables of 120
Ω
impedance or one double screened cable of the
same impedance.
The following rules should be observed to meet the requirements concerning noise
emissions. Symmetric cables should be connected using DSUB-25 plug equipped with a metal or
metalized casing (shield) and the cable screen should be connected to the casing over the whole
circumference. It is insufficient just to connect the screen to the "structural earth" terminals on
the E1/G.703 120
Ω
interface socket.
The E1/G.703 120
Ω
linear module socket outputs are described in Table 5.
Table 5.
Description of TM-77 and MD-77 E1/G.703 120
Ω
interface outputs
Pin
No.
Description of outputs
1 GND
2 RX_B4
3 TX_B4
4 RX_A3
5 TX_A3
6 GND
7 RX_B2
8 TX_B2
9 RX_A1
10 TX_A1
11 GND
12 GND
13 Not
connected
14 RX_A4
15 TX_A4
16 GND
17 RX_B3
18 TX_B3
19 RX_A2
20 TX_A2
21 GND
22 RX_B1
23 TX_B1
24 GND
25 Not
connected
