[Asterisk-Users] SIP outbound call audio quality change

[Paul]

I recently hooked up my sipura IP phone and set it up as an SIP device to
connected to asterisk. I am able to dial a number on the SIP phone, connect
to an external number via the PSTN connected to asterisk and begin the
conversation. At first, the audio quality is PERFECT, in both directions. I
can hear the person clearly and they claim to hear me like im on a regular
POTS line. After approximately 1 minute, the quality turns horrible and the
person can no longer hear me, but I can faintly here them. There is a lot of
static on the line, it almost sounds like an electronic device is
interfering with it. I thought maybe it was a wireless phone or router, so I
disconnected all those and put my cell phone in the other room. Still no
change. Anyone have any ideas? 

Paul