I installed an Asterisk based solution that is giving problems with the incoming isdn30 trunk.
isdn30 -> Asterisk -> Tenovis pbx -> 300 tenovis phones and 2 faxes
This is connected, registered and handled on the Asterisk box.
-2 faxes connected
by Grandstream ATA’s
In the server there is a Sangoma 2 * E1 card without hardware echo cancelation. One of the ports is used for the incoming isdn30 trunk of the telco and the other to connect the asterisk box with the Tenovis PBX
Once in a while (a couple of times a week) the incoming isdn30 is losing incoming and outgoing connection. Lights on the card stay green and there is no alarm and no trace in the loggings. When making an outgoing call during an incident there is a busy tone (that can’t be provided by the Asterisk box I suppose). To get back in business one has to plug out and plug in the cable and, if this doesn’t help, restart the server.
During an incident all channels of the incoming isdn-trunk gives the following message:
Zaptel Disabled echo canceler because of tone (rx) on channel …
Zaptel Disabled echo canceler because of tone (tx) on channel …
last two lines on screen
Zaptel: Master changed to WPE/1
Zaptel: Master changed to WPE/0
For the same channel the message appears several times.
The telco has done tests and is monitoring the trunk. They are really doing the best they can and they discovered some what they call “slips” but they don’t match with the incidents. We changed the cable for a new one of the best quality available and updated the system but the problem is still there.
This is what makes the server:
-Scopserv is installed as the gui.
I asked questions on the irc channel and one suggested that the cause could be faxes. Could there really be any relation between the problem and incoming or outgoing faxes and what should be the probem. Does the message indicate that the Asterisk server is to blame or could there be a problem on the telco side. Any suggestion or pointer to resolve this problem is very much appreciated.