Specifications

Macrotel DIGITAL

Pag. 13

5 OPERATION

5.1

RAINING THE TELEPHONE ECHO CANCELLER

Upon connection to the telephone line, the digital hybrid will automatically begin its telephone echo

cancellation process. This will optimize the send to caller separation. If the send to caller separation is not

sufficient, you may force the hybrid to .train. itself to the telephone line by pressing and holding the ON

button for one second. After one second, the hybrid will emit a burst of white noise. The noise burst allows

the hybrid to aggressively adapt to the echo returning from the telephone network and allows the hybrid to

maximize its send-to-caller separation.

This noise burst can be generated at any time by pressing and holding the ON button for one second. To

force a noise burst on every connection to the telephone line, activate the BURST ADAPT DIP SWITCH 1.

See .DIP Switches setting at the previous Chapter.

5.2 TRAINING THE MIX-MINUS

Upon connection to the telephone line, the digital hybrid will automatically begin its mix-minus echo

cancellation processes. To verify/fine tune the calibration of the mix-minus, watch the SEND LED as the

caller speaks. If the SEND LED is not lighting or only flashing green on the caller.s audio peaks, then the

calibration is already complete. If the SEND LED is lighting solid green on caller audio, decrease the loop

gain via the SEND INPUT pot or the console level control and train the telephone echo canceller. As the

caller continues to speak, you should notice that the SEND LED will begin to illuminate less and less until it

no longer lights green on caller audio. This process may need to be repeated if the desired results are not

achieved or if the caller is complaining of excessive echo.