Nortel Networks Circuit Card User Manual

 NT8D02 and NTDK16 Digital Line cards

The digital line card needs +15V DC over each loop at a maximum current of 
80 mA. It requires +15V, -15V, and +5V from the backplane. The line feed 
interface can supply power to one loop of varying length up to 1070 m 
(3500 ft) using 24 AWG wire with a maximum allowable AC signal loss of 
15.5 dB at 256 kHz, and a maximum DC loop resistance of 210 ohms; 
26 AWG wire is limited to 745 m (2450 ft).

In-circuit protection against power line crosses or lightning is not provided on 
the NT8D02 Digital Line card. The NT8D02 Digital Line card does, 
however, have protection against accidental shorts to –52 V dc analog lines. 

When the card is used to service off-premise telephones, primary and 
secondary Main Distribution Frame (MDF) protection must be installed.

Off-premise telephones served by cable pairs routed through the central 
office, or crossing a public right-of-way, can be subject to a requirement for 
on-card protection, and MDF protectors may not be acceptable. Check local 
regulations before providing such service.

±5.0 V dc

150 mA

+15.0 V dc

1.6 Amp

–15.0 V dc

1.3 Amp