Nortel Networks BCM200/400 - Manual (Page 179)

Chapter 11 Installing the analog terminal adapter 179
BCM200/400 4.0 Installation and Maintenance Guide
Figure 86 Insertion loss from the CO to the analog telephone
Measure the total insertion loss between the CO and analog device by using standard dial-up test
lines with a transmission test set (for example, Hewlett-Packard 4935A Transmission Test Set).
To measure the insertion loss from the CO to the analog device
1 Establish a connection to the 1 mW, 1 kHz, CO service line with an analog telephone attached
to the ATA2.
2 Ensure that the analog port terminates correctly in 600 ohms:
• Replace the analog telephone with the test set.
• Use RECEIVE/600 OHM/HOLD mode on the test set.
3 Ensure that the test set connects in parallel to the service line before removing the analog
telephone or the line drops.
4 Remove the single-line telephone.
5 Measure the 1 kHz tone at the far end of the analog port, which is where the analog loop ends
and where the analog device connects.
To measure the insertion loss from the analog device to the CO
1 Establish a connection to a silent termination on the CO service line with an analog telephone
attached to the ATA2.
2 Make sure the analog port terminates correctly in 600 ohms:
Longitudinal balance to ground 50 dB
60 to 4,000 Hz
With IEEE 455-1976 test
Overload level 3 dB
Note: The tone must be greater than - 10 dB (for example, - 9 dB is acceptable).
Analog telephone
ATA 2
BCM main unit
BCM to ATA 2
ATA 2 to BCM
10 dB Max
Cable loss
Central Office
cable loss