Nortel Circuit Card Installation Manual page 618

Page 618 of 906
Table 192
Trunk types – termination impedance and balance network (NT8D14BA, NT8D14BB)
Trunk types
CO/FX/WATS
2-way TIE (LDR)
2-way TIE (OAID)
DID (loop length
< 600 ohms)
DID (loop length
Š 600 ohms)
RAN: continuous
operation mode
Paging
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.
Jumper strap settings
553-3001-211 Standard 3.00
NT8D14 Universal Trunk card
Terminating
impedance
(Note 1)
600 or 900
ohms
600 or 900
ohms
600 or 900
ohms
600 or 900
ohms
600 or 900
ohms
600 or 900 600 or 900 ohms
ohms
600 ohms
For most applications, the jumper strap settings remain set to the standard
configuration as shipped from the factory. See Table 190 on
The jumper strap settings must be changed, as shown in Table 191 on
page 617, for the following:
• For CO/FX/WATS or TIE trunk loops exceeding 1524 meters (5000 ft.)
August 2005
Balance network for loop lengths (Note 2)
0–915 m 915–1524 m
(0–3000 ft) (3000–5000 ft)
600 ohms
600 ohms
600 ohms
600 ohms
600 ohms
600 ohms
> 1524 m
(> 5000 ft)
3COM
3COM
3COM
3COM
N/A
N/A
N/A
page
3CM2
3CM2
3CM2
3CM2
3CM2
N/A
N/A
616.