Summary:ASTERISK-00397: Calls from IAX to Zap PRI have audio quality problems
Reporter:lele (lele)Labels:
Date Opened:2003-10-18 03:03:46Date Closed:2011-06-07 14:04:50
Versions:Frequency of
Description:i'm using a TE410P on some E1/PRI with EuroISDN and experiencing a few audio quality problems with current CVS (both zaptel and asterisk) and the following network

ISDN public                                                   SIP/zaptel
network ---- pri --- ASTERISK GW --- iax --- ASTERISK PBX --- PHONES
                                w/ any codec

the rx (public network to local phone) audio channel is audibly too loud and peaks are clipped as if something in the path is increasing the level of about 3dB on both SIP and zaptel phones.
Prompts on ASTERISK GW are unaffected, only audio coming from the PRI is distorted. Also, ASTERISK PBX has a chan_capi device, which has good audio as well.

Setting 'rxgain=-3.0' on the ASTERISK GW fixes the problem but it looks to me there must be something wrong if alaw digital voice coming from the ISDN network is clipped when going through an iax channel.
Comments:By: Mark Spencer (markster) 2003-11-04 23:26:13.000-0600

Are you sure there are no other gain things going on?

By: lele (lele) 2003-11-05 07:12:51.000-0600

Yes, sure. I'm experiencing it in 3 independent installations, all of them have similar topology (ie: sip phones->asterisk->iax->asterisk->zaptel PRI). It seems to be related with the iax in the middle because when I replace it with SIP the level does not get increased. I'll dig in it and post more info asap.

By: zoa (zoa) 2004-01-09 19:25:35.000-0600

on 3 of my 4 spans of my TE410p i have problems with distorted sound when a call comes in.

the 4 spans are connected to 4 different switches, i'll go on site and try to see what happens if i switch some cables. (although i higly suspect it to be a problem with the switches).

any others with problems ?

By: Brian West (bkw918) 2004-01-11 03:50:52.000-0600

Are you using IAX2?

By: Brian West (bkw918) 2004-01-28 00:07:12.000-0600

Unable to dupe.. seems to be a local network issue.