AT&T SB67040 User Manual page 255

To resolve audio echo issues: (Continued)
4. If the loss number is below 10, the system will most often function normally, but there is an increased likelihood of audio
performance issues like echo. If the loss number is below 10 the following procedures can be used to increase the loss
value:
a. Unplug that telephone line at the Gateway.
b. After the line LED turns red, plug the line back in to recalibrate.
5. If the recalibration has no effect, a parallel device such as a fax adapter, alarm system, DSL modem, or DSL splitter/filter
may be connected to the system. Parallel external devices may affect line calibration. Temporarily disconnect these
devices from the telephone wall jacks that are connected to the same telephone lines, as follows:
a. Unplug these non–system external devices from their telephone wall jacks.
b. Unplug the telephone line connections from the Gateway.
c. After the Gateway Line-Status LEDs turn red, plug the telephone lines into the Gateway again to recalibrate.
d. If there is a significant increase in the loss number and improved audio performance on those lines after disconnecting
a parallel device, consult your telephone service provider to either investigate the problem or to install separate lines
for those parallel devices.
Troubleshooting
Synapse User's Guide
255