Nortel 1750, Install Manual

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Appendix A Technical specifications
NN46110-316 02.01
You connect the T1/E1 CSU/DSU WAN interface card to the service provider
network using a straight-through cable or a crossover cable, depending on how the
service provider wired its jack.
• For a straight-through connection, you can use a standard Category 5
(Ethernet) straight-through cable.
• For a crossover connection, you cannot use a standard Category 5 crossover
cable. D not interchange the T1/E1 CSU/DSU crossover cable and the
Ethernet crossover cable.
Table 29 provides the T1/E1 CSU/DSU cable pinouts for a crossover connection.
The cable operates properly if you do not connect pins 3, 6, 7, and 8.
Table 29
T1/E1 CSU/DSU cable pinouts for crossover connection
Standard-wired
end 8-pin male Signal name
Pair number
and conductor
Special-wired
end 8-pin male
1 RXDA<-TXDA wht/org pair 2A 5
2 RXDB<-TXDB orange pair 2B 4
3 not used wht/grn pair 3A 3
4 TXDB->RXDB blue pair 1B 2
5 TXDA->RXDA wht/blu pair 1A 1
6 not used green pair 3B 6
7 not used wht/brn pair 4A 7
8 not used brown pair 4B 8
Caution:
For crossover connections, do not use Ethernet cable. If you
use Ethernet cable, the T1/E1 CSU/DSU does not work to specifications,
and this condition can corrupt data.