Nortel DMS-100 Series Maintenance Manual page 42

1-26 OPM maintenance summary
Line drawer current demand with all lines on-hook
The following table shows the base current demand for the OPM with line
drawers, line cards and all lines on-hook:
Table 2 Frame current with line drawers supplied
Drawers
0
1
2
3
4
5
6
7
8
9
10
Current demands with line off-hook
The amount of current drawn by an off-hook line depends on the length of the
loop.
For these calculations, an NT6X17AA line card has the following parameters:
•
•
•
•
Use the above values to calculate the off-hook line power requirements. For
example:
•
•
The call rate of 3.0 CCS or about 8.3% of the installed lines off-hook
determines the calculated percentage of installed lines that are off-hook. For
297-8361-550 Standard 04.02 December 2004
line card battery feed resistors = 440 Ω
telephone resistance = 200 Ω
assumed short loop resistance = 50 Ω
assumed average loop resistance = 800 Ω
off-hook current for short loop = 77 mA
off-hook current for average loop = 40 mA.
Line cards
0
64
128
192
256
320
384
448
512
576
640
Frame current demand
(A)
9.0
9.38
9.76
10.14
10.88
11.26
11.64
12.02
12.40
12.78
13.16