Measure the echo-return loss on voicetronix fxo telephony modules
vdaaerl [options]
The vdaaerl utility tests the echo-return from a telephone line connected to a Voicetronix FXO module, such as those used on the OpenPCI range of cards. It can scan all available impedance values to find the best match for a particular line.
It will wait for an incoming call on the port under test. The calling handset should have the microphone well muted for the duration of the test.
A series of tones will be played down the line to determine the ERL in several parts of the audio spectrum. You should avoid creating any other noise on the line while this test is running, or the results may be skewed.
If no --impedance is specified, and the --scan option is not used, then the default impedance value (based on the port's country selection) will be used.
The following options are available:
--help, -?
Show summary of options.
--card number
Explicitly select the card to test. Default is card 0.
--port number
Explicitly select the port to test. Default is port 0 of the card being tested.
--impedance number
Test a particular impedance setting [0 - 15].
--scan
Test all available impedances.
--playgain db
Set the hardware play gain. Values may range from -12.0 to 12.0.
--recgain db
Set the hardware record gain. Values may range from -12.0 to 12.0.
Ron Lee, Peter Wintulich, David Rowe, Voicetronix <[email protected]>
This manual page was written by Ron <[email protected]>, for the Debian project (but may be used by others).