[asterisk-users] Re: PSTN Calls from SI.P: buzzing and pops

[Allen Casteran]

Tzafrir Cohen wrote:
> On Fri, Feb 16, 2007 at 12:39:54AM -0500, Allen Casteran wrote:
> 
>>We have SIP phones connecting to *, and our PSTN lines connecting 
>>through an Astribank FXO.
>>
>>Internal Sip<->SIP calls are clear.
>>External calls through the Astribank get occassional low level buzzing 
>>for about 1/2 - 1 sec at a time.
>>
>>Those are usually accompanied by some light pops or static
>>
>>No transcoding, all ulaw.
>>PSTN lines come from an Adtran IAD channel bank about 10 ft of cable 
>>from the Astribak. Astribank and Adtran are both chassis grounded to our 
>> UPS.
>>
>>Tried set echocancel=on and echocancel=off in the zapata.conf... No 
>>difference.
> 
> 
> You mentioned (in another mail) that if you connect the same line to the
> PSTN the line is clear. Was it in the same setup or were there some
> resets and/or reconfigurations in the process?
> 
> If you connect a simple phone insted of the Astribank, do yu have the
> same problems?

Same setup.
We replaced analog phones with the * Server and then noticed the 
buzzing.  Before installing the * server the analog phones had been used 
on the same lines with no problems for about a year. No changes have 
been made to the lines themselves.

The buzz occurs every minute or so, but not on any schedule that I can 
determine. (ie not every 65 seconds).
I have done several config changes on the * server to try and eliminate 
the problem to no avail.