Nortel Circuit Card Installation Manual page 538

Page 538 of 906
Power requirements
Foreign and surge voltage protections
553-3001-211 Standard 3.00
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).
Table 174
Digital line card—power required
Voltage
±5.0 V dc
+15.0 V dc
–15.0 V dc
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.
August 2005
Current (max.)
150 mA
1.6 Amp
1.3 Amp