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[jlamanna at gmail.com]

Hi,
I've noticed that sometimes instead of getting a regular ring tone
when calling out on a Zap channel, I get this obnoxious loud noise
which forces me to hang up.
Is this a problem in the Zaptel driver? I seem to recall that ringback
tones are generated by zaptel when dialing out from a SIP phone over a
Zap trunk.

Thanks.

[rob at hillis.dyndns.org]

In my experience, the ringback you get over a zap channel (be it
analogue or digital) is generated by the remote end, /not/ Zaptel.

The ringback you get over a SIP or IAX2 channel is often generated by
either Asterisk or the SIP/IAX2 device you're calling from.
James Lamanna wrote:

[jlamanna at gmail.com]

Hmm ok.
This was a call from a SIP phone registered with Asterisk outbound on
a Zap trunk.
So would Asterisk or the phone be generating the ringback tone in that case?

It also happens very intermittently (maybe 1 in 10 calls at most...)

-- James

Rob Hillis wrote:

[rob at hillis.dyndns.org]

The ringback is coming from the Zap channel, since that's the
destination of the call. Therefore, the "bad" ring is more likely to be
coming from the remote end.

What type of line are you making the call to? Analogue? E1/T1? If
it's analogue, I'd be guessing you have a faulty PSTN line.

James Lamanna wrote: