Technical summarv 9
Power requirements
-

NT8DOSAB

The NT8DO9AR Analog Message Waiting Line Card has the following
power requirements:
Table 4
Power requirements
Voltage
(+/-I
+
12.0Vdc
+ 8.0 Vdc
-
48.0 Vdc
-
48.0 Vdc
88.0 V ac
-150.0 V dc
Tolerance Idle
Active
current current
0.36 V dc 48 ma Oma
8ma
40 ma
(1) 10 ma
(2) 10 ma
2ma
1
Max
48
ma
280ma
688ma
320ma
160 ma
32ma
Note:
(1) Each active ringing relay requires 10 ma of battery voltage.
(2)
Reflects the current for ringing a single station set. There
may be as many as five ringers on each line.
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Foreign and surge voltage protections
When telephone lines connected to the line circuit are exposed to foreign
voltages by direct contact or induction (for example, power line crosses or
lightning), protection devices must be installed on the customer’s premises.
These devices must be capable of providing a path to ground from tip and
ring for foreign voltages that exceed 600 V peak.
Overload level
Signal levels exceeding + 7 dBm applied to the tip and ring cause distortion
in speech transmission.
Analog message waiting line card description 553-3001-l 63