Direct Dial Inward Description - Nortel Meridian 1 Manual

Page 34 of 44 Direct Dial Inward trunk card
Pad switching

Direct Dial Inward description

Supplement to 553-3011-210
Table 22
NT5K17BA Environmental specifications
Parameter
Operating temperature
Operating humidity
Storage temperature
Loss values for the NT5K17BA DDI trunk card are as follows:
Table 23
NT5K17BA loss values
CO line loss
0 to 3 dB
3 to 6 dB
Each unit on the NT5K17BA DDI card operates as a DDI trunk. Table 3-8
presents a summary of NT5K17BA DDI trunk card signalling states.
Idle State
When the central office presents a high impedance of 8.5K ohms or greater to
the DDI unit, the NT5K17BA DDI trunk card is in the idle state. Ground is
present on the tip wire and negative battery (-50V) is present on the ring wire.
Seize
The central office initiates a call by placing a low resistance loop (2.2 K ohms
or less) across the tip and ring leads. The increased current flow will trigger
a front end detector on the Option 11. A message is sent to the Central
Processing Unit (CPU), and the microprocessor prepares for receipt of
dialling digits. A seizure acknowledge signal is sent to the central office
within 150 milliseconds.
Provisional 1.3
Specifications
0 to 50 degrees C, ambient
5 to 95 % RH (non-condensing)
- 50 to + 70 degrees C
Analog-to-Digital
-6 dB
-8 dB
July 1993
Digital-to-Analog
0 dB
-3 dB