Nortel Networks 553-3001-211 manual Input impedance, Insertion loss, Frequency response

NT8D09 Analog Message Waiting Line card Page 543 of 894

Analog line interface

Input impedance

The impedance at tip and ring is 600 ohms with a return loss of:

•20 dB for 200-500 Hz

•26 dB for 500-3400 Hz

Insertion loss

On a station line-to-line connection, the total insertion loss at 1 kHz is

6 dB + 1 dB. This is arranged as 3.5 dB loss for analog to PCM, and 2.5 dB loss for PCM to analog.

Frequency response

The loss values in Table 173 are measured relative to the loss at 1 kHz.

Table 173

Analog message waiting line card – frequency response

Frequency (Hz)

Minimum (dB)

Maximum (dB)

60

20.0

—

200

0.0

5.0

300

–0.5

1.0

3000

–0.5

1.0

3200

–0.5

1.5

3400

0.0

3.0

Message channel noise

The message channel noise C-weighted (dBrnC) on 95 percent of the connections (line to line) with both ends terminated in 600 ohms does not exceed 20 dBrnC.

Circuit Card Description and Installation