Nortel Networks Circuit Card Manual

A SERVICE OF

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NT8D14 Universal Trunk card Page 621 of 906

Circuit Card Description and Installation

Table 193

Trunk types – termination impedance and balance network (NT8D14BA, NT8D14BB)

Trunk types

Terminating

impedance

(Note 1)

Balance network for loop lengths (Note 2)

0–915 m

(0–3000 ft)

915–1524 m

(3000–5000 ft)

> 1524 m

(> 5000 ft)

CO/FX/WATS 600 or 900

ohms

600 ohms 3COM 3CM2

2-way TIE (LDR) 600 or 900

ohms

600 ohms 3COM 3CM2

2-way TIE (OAID) 600 or 900

ohms

600 ohms 3COM 3CM2

DID (loop length

< 600 ohms)

600 or 900

ohms

600 ohms 3COM 3CM2

DID (loop length

Š 600 ohms)

600 or 900

ohms

600 ohms N/A 3CM2

RAN: continuous

operation mode

600 or 900

ohms

600 or 900 ohms N/A N/A

Paging 600 ohms 600 ohms N/A N/A

Note 1: The terminating impedance of each trunk unit is software selectable in LD 14 and

should match the nominal impedance of the connecting equipment.

Note 2: The balance network of each trunk unit is software selectable between resistive 600 or

900 ohms or 3COM and jumper selectable between 3COM and 3CM2. Jumper selection for

3COM/3CM2 restriction does not apply to NT8D14BB.