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Chapter 13 Installing Analog Terminal Adapters 199
Installation and Maintenance Guide
Insertion loss measurement
Measure the total insertion loss between the CO and voice messaging device by using standard dial
up test lines with a transmission test set. For example, Hewlett-Packard 4935A Transmission Test
Set.
For CO to analog device measurement
To measure the insertion loss from the CO to the voice messaging device:
1 Establish a connection to the 1 mW, 1 kHz, CO service line with a single-line telephone
attached to the ATA 2.
2 Ensure that the analog port terminates correctly in 600 ohms:
a Replace the single-line telephone with the test set
b 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 single-line
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 voice messaging device connects.)
For analog device to CO measurement
To measure the insertion loss from the voice messaging device to the CO:
1 Establish a connection to a silent termination on the CO service line with a single-line
telephone attached to the ATA 2.
2 Make sure the analog port terminates correctly in 600 ohms by:
• replacing the single-line telephone with the test set
• using
TRANSMIT/600 OHM/HOLD mode on the test set
3 Make sure the test set connects in parallel to the service line before removing the single-line
telephone or the line drops.
4 Remove the single-line telephone.
5 Introduce a 1 kHz tone into the analog line at - 10 dBm, and measure the level at the CO
exchange.
Note: The tone must be greater than - 10 dB (for example: - 9 dB is acceptable).
Note: The difference in levels is the transmit loss and must be less than 10 dB
(for example, 9 dB is acceptable).