[asterisk-dev] Problem with phantom rings....

Mike Jagdis mjagdis at eris-associates.co.uk
Mon Mar 26 02:40:11 MST 2007

On Mon, Mar 26, 2007 at 11:22:35AM +0300, Marius Stankevičius wrote:
> A problem is noisy line.... every 2-5 minutes (even if there was no previous
> activity) I get noise that registers as an incoming call on CO line. If the
> call gets picked up it gives dialtone (Digium TDM400P card with 4 FXO
> ports). It _is not_ voicemail. Caller ID set to yes and it is not a polarity
> issue (turned that off)

If it's that bad and it's unfixable by your provider (a) I hope you're
not paying them and (b) the problem is the ring detection at the
driver/hardware level.

The hardware ring detection is tunable to some extent, but I really
couldn't say in what way (although the "how" is just tweak some

Fortunately wctdm.c also has an alternate, driver level ring detection
routine. Try uncommenting AUDIO_RINGCHECK near the top of wctdm.c.
You may also need to tweak MINPEGTIME, PEGTIME and PEGCOUNT further
down. (Note: the AUDIO_RINGCHECK code may not be as well tested...)


Mike Jagdis                        Web: http://www.eris-associates.co.uk
Eris Associates Limited            Tel: +44 7780 608 368
Reading, England                   Fax: +44 118 926 6974

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