Echo and key presses

Hi all,

I’m hoping to get some ideas on where to troubleshoot the following: we use an 8 ports Beronet ISDN card to connect a legacy PBX to a Asterisk box. Completely random we get heavy echo on the incomming calls. Also we hear DTMF sounds during conversations, while people didn’t press down keys on their telephones. The ISDN card is configured as TE PTP.

Thanks for any suggestions,


Do you have echo cancellation set in zapata.conf ? To see if DTMF is actually being keyed in set verbose,debug,dtmf under full in logger.conf. Look at the log file and see if keys are actually are being pressed. If the user on the other line is not pressing them I would speak to your carrier about it.


thx for replying.
Is zapata.conf relevant for isdn? I did see some echo cancellation settings in misdn.conf. But since the echo is not always there, I’m wondering if they are going to work.
I’m sure keys are not pressed, because I experienced it with colleagues and they assured me not having touched anything. I did find some settings for DTMF (dtmftreshold in misdn-init.conf and relaxdtmf in sip.conf). I’ve changed both.