[Asterisk-Users] Buzzing on TDM400P FXS?

[Scott Laird]

I have an intermittent problem with the one FXS line that I have.  On 
most calls, the first ~5 seconds of the call has a loud buzzing noise 
on the line.  After 5 seconds or so, it fades off to nothing, and the 
sound quality is great.  Searching for "buzzing" on the list doesn't 
give a whole lot to work with.  The buzzing happens on calls that are 
routed over both my FXO line and IAX to NuFone, so I'm pretty sure that 
it's happening on the FXS end.

Here's that chunk of zapata.conf:

  context=inside-analog
  signalling=fxo_ks
  callwaiting=yes
  callwaitingcallerid=yes
  cancallforward=yes
  callreturn=yes
  threewaycalling=yes
  transfer=yes
  echocancel=yes
  echocancelwhenbridged=yes
  relaxdtmf=yes
  rxgain=1.5
  txgain=0
  immediate=no
  musiconhold=yes
  usecallerid=yes
  callerid="Analog Phone" <2201>
  mailbox=2201
  channel => 2

Does anyone have any suggestions on where to start looking?


Scott