Nortel Networks Circuit Card 311 - Manual (Page 697)

Configuration 697
Balance network for loop lengths (Note 2)
Trunk types
Terminating
impedance
(Note 1)
0–915 m
(0–3000 ft)
915–1524 m
(3000–5000 ft)
> 1524 m
(> 5000 ft)
RAN: continuous
operation mode 600 or 900
hms 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.
Table 254
Cable loop resistance and loss
Cable loop resistance (ohms)
Cable loop loss (dB)
(nonloaded at 1kHz)
Cable length 22 AWG 24 AWG 26 AWG 22 AWG 24 AWG 26 AWG
915 m (3000 ft.) 97 155 251 0.9 1.2 1.5
1524 m (5000 ft.) 162 260 417 1.6 2.0 2.5
2225 m (7300 ft.) 236 378 609 2.3 3.0 3.7
3566 m (11700 ft.) 379 607 977 3.7 4.8 6.0
5639 m (18500 ft.) 600 960 1544 5.9 7.6 9.4
The trunk type, terminating impedance, and balance network are selected by
making service change entries in the Trunk Administration program LD 14.
Refer to Table 257 "Trunk types - termination impedance and balance
network (NT8D14BA, NT8D14BB)" (page 699) to select the proper values
for the trunk type and loop length being employed.
Refer to Meridian 1 Software Input/Output Reference — Administration
(NN43001-611) for LD 14 service change instructions.
Before the appropriate balance network can be selected, the loop length
between the near-end (Meridian 1) and the far-end (a Central Office, for
example) must be known. To assist in determining loop length, some typical
resistance and loss values for the most common cable lengths are given
in
Table 258 "Cable loop resistance and loss" (page 700) , for comparison
with values obtained from actual measurements.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
.