I find that if I drop the RX gain too much I start to lose DTMF decoding. The Asterisk calls lose at least 3-6db end-to-end compared with a "normal" call. If I bring the gain up, the symptoms sound exactly like yours.
The gain I am using is more like Rx=-2, Tx=0 but this is still quite quiet. I guess that line impedance mismatch between US and European standards accounts for some of the gain loss. Peter -----Original Message----- From: Mike Benoit [mailto:[EMAIL PROTECTED] Sent: 28 June 2004 21:59 To: [EMAIL PROTECTED] Subject: Re: [Asterisk-Users] Zap X100P oscillation I wonder if your issue and mine are related somehow. I have a asterisk server with 4 FXO cards in it, and when a call comes in one ZAP channel, then dials out another, I hear what could be described as a steam engine starting up. It starts off kinda slower/ quiet, then quickly (in about 2-4 seconds) completely over powers the line. The only way I could stop it was by adjusting the gains. rxgain=-8.5 txgain=4 Seemed to do the trick. As did: rxgain=-6.5 txgain=1 An rxgain of even -8.0 or -6.0 in either case would result in this "steam engine" sound. -8.5 or -6.5 would make it go away completely. I'm using a CVS checkout from yesterday, and I tried with both echotraining=800 and turning echo cancellation off completely. Neither made any difference. It would be really nice to be able to use a positive rxgain value. I haven't tried with the echo app, but using just one FXO card works fine with almost any rx/txgain value. As soon as the call utilizes two FXO card at the same time, the "steam engine" sound occurs. On Mon, 2004-06-28 at 16:26 +0100, Whisker, Peter wrote: > Has anyone seen this problem before? > > I have a server with a single X100P card. The audio level is a low, but if I > raise the gain to more than -2db (Rx + Tx) it starts to oscillate in an echo > test. Not at a high frequency but with a noise that is best described as a > steam engine starting up. It then starts to clip and crackle. If I bring the > gain down to Rx=-2.0 and Tx=0.0 or lower then it settles down but it is very > very quiet. > > I have tried the latest CVS Head with echotraining=800 set and also complied > with the aggressive echo cancelling, but nothing seems to help. > > Ideas welcome! > > Many thanks > Peter Whisker > > This e-mail and any attachment is for authorised use by the intended recipient(s) only. It may contain proprietary material, confidential information and/or be subject to legal privilege. It should not be copied, disclosed to, retained or used by, any other party. If you are not an intended recipient then please promptly delete this e-mail and any attachment and all copies and inform the sender. Thank you. > _______________________________________________ > Asterisk-Users mailing list > [EMAIL PROTECTED] > http://lists.digium.com/mailman/listinfo/asterisk-users > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users -- Mike Benoit <[EMAIL PROTECTED]> _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users This e-mail and any attachment is for authorised use by the intended recipient(s) only. It may contain proprietary material, confidential information and/or be subject to legal privilege. It should not be copied, disclosed to, retained or used by, any other party. If you are not an intended recipient then please promptly delete this e-mail and any attachment and all copies and inform the sender. Thank you. _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
