DAHDI Sidetone Loud on FXO


Only on my DAHDI FXO line the sidetone is very loud. Is this the FXO line or is there any contribution from DAHDI?


Can the extra loud side tone be heard on both ends, or just the PBX phone? What phones are you using with the PBX? Also, is it only the sidetone that’s loud, and rest of the call audio, such as the voice sounds fine?



dahdi_monitor --vv 'channel number'

in one console , then from inside asterisk on another console

channel originate LOCAL/5036971000@DAHDI/(testing channel) application milliwatt

you will be watching a good old stereo vu -meter of a milliwatt test on the outside and one on the inside, it is your job to adjust the rx/tx gains on the dahdi channels to make it ‘look pretty’


Still not sure how the sidetone is generated. Is it created within the PBX? Since the levels on my VOIP lines are good, it is somehow related to the POTS line. TX level adjustment might help if the sidetone is generated by the PBX.


The “sidetone” is ‘best-effort’ by the 2-4 wire hybrid bridge DAHDI mixes from. Balance the bridge for best effect. as suggested, Tune the impedance if analog previiusly with fxotune to reduce echo tail

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