Nortel Networks Circuit Card Benutzerhandbuch

 NT8D14 Universal Trunk card

Table 185 gives the electrical characteristics of the NT8D14 Universal Trunk 
card.

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

Ring detection

17 to 33 Hz
40 to 120 V rms

N/A

N/A

N/A