NT8D14 Universal Trunk card Page 597 of 894
Circuit Card Description and Installation
Electrical specifications
Table 180 gives the electrical characteristics of the NT8D14 Universal Trunk
card.
Table 180
Universal trunk card – trunk interface electrical characteristics (Part 1 of 2)
Trunk Types
Characteristic CO / FX / WATS DID / TIE RAN Paging
Terminal impedance 600 or 900 ohms
(Note 1)
600 or 900 ohms
(Note 1)
600/900 ohms
(Note 1)
600 ohms
Balance impedance 600 or 900 ohms
(Note 1),
3COM, or 3CM2
(Note 2)
600 or 900 ohms
(Note 1),
3COM, or 3CM2
(Note 2)
N/A N/A
Supervision type Ground or
loop start
(Note 3)
Loop start
(with ans sup)
(Note 3)
Continuous, level, or
pulse
N/A
DC signaling loop
length (max)
1700-ohm loop with
near-end battery of
–42.75 V
2450-ohm loop with
near-end battery of
–44 V
600/900-ohm loop 600 ohm
loop
Far-end battery –42 to –52.5 V
(Note 4)
–42 to –52.5 V –42 to –52 V N/A
Minimum detected
loop current
20 mA 10 mA 10 mA N/A
Ground potential
difference
±3 V
±3 V
±1 V ±1 V
Low DC loop
resistance during
outpulsing
<300 ohms N/A N/A N/A
High DC loop
resistance
Ground start
Š 30k ohms;
loop start
Š 5M ohms
N/A N/A N/A