Basically if you hear this, it's the PAP2 interpreting a sound/voice as DTMF. By default it essentially "listens" for a DTMF tone and if it "hears" a hint of what it thinks is one, it'll generates it. This is why it only happens to some people (the sound/voice has to be the pitch/sound its looking for. This has been going on for years with those.

If you do experience, here's what you can do.

1) Go to vPanel - Features - Preferences - Advanced and set your DTMF Method to Inband. This will require the adapter to reboot.

2) If you still have it the, go to vPanel - Features - Preferences - Advanced and set your Audio to pass through the VOIPo network (more strict with DTMF).

It should be able to be resolved 99% of the time with these two things.