Nortel Circuit Card, Installation Manual, Page: 166 / 908

Page 166 of 906 NT1R20 Off-Premise Station Analog Line card
553-3001-211 Standard 3.00 August 2005
Analog line interface
Table 64 lists the electrical characteristics of NT1R20 OPS analog line card
line interface units.
Table 64
OPS analog line card – electrical characteristics
Characteristic Specification
Terminal impedance (TIMP) 600 or 900 ohms
Balance impedance (BIMP) 600 or 900 ohms, 3COM, or 3CM2
DC signaling loop length (max) 2300 ohm loop (including resistance
of telephone) with nominal battery of
–48 V dc
Battery supply voltage –42 to –52.5 V dc
Minimum detected loop current 16 mA
Ground potential difference ± 3 V
Line leakage > 30k ohms, tip-to-ring,
tip-to-ground, ring-to-ground
AC induction rejection 10 V rms, tip-to-ring,
tip-to-ground, ring-to-ground