[asterisk-users] Noise on FXS ports (Sangoma)

[Stephen Bosch]

Stephen Bosch wrote:
> Stephen Bosch wrote:
>> Hi:
>>
>> I have a Sangoma A200 card installed in a server with two FXO modules
>> and one FXS module.
>>
>> Analog sets connected to the FXS module have a "squeaky static" -- it's
>> like static mixed with the sound of someone vigorously cleaning a window
>> a few doors down.
>>
>> In other words, it's not a classic static noise, but it is noise, and
>> it's distracting. Remote callers can hear this noise.
>>
>> I have, by turns:
>>
>> - Tested the line with the same analog sets plugged in at the
>> demarcation point. No noise. (None of the SIP devices in this
>> configuration have this noise for outgoing calls, so I'm sure it's got
>> something to do with the FXS module).
>>
>> - Plugged the known good analog sets straight into the server
>>
>> - Moved the FXS module off the REMORA daughtercard to the main card
>>
>> - Replaced the FXS module with a new one
>>
>> - Run the server off of battery power, to see if the noise is garbage
>> leaking in off the AC
>>
>> - Turned off the PoE midspan
>>
>> The next thing I'm going to try is turning off the switch it's plugged
>> into. When that is done, I'll have done everything short of move the
>> server to a different location.
> 
> Maybe the power supply is generating this crap.
> 
> Hmn. I'm going to test this hypothesis.

Okay -- that didn't work. I swapped the power supply out with a better
one, and even disconnected the extra ventilation fan. The noise is
different but still there.

To those with experience with FXS modules, I welcome your input.

-Stephen-