User presses Dial Button, an incoming call is picked up

I’ll put the system details below. First, here’s the symptom: a user makes a call by pressing the Dial or Send button. Instead of dialing out, it happens to pick up an incoming call that was being received right at that moment. This is intermittent, but has been occurring more frequently. Incoming calls are suppose to go to an IVR and then routed to the proper Ring group or person.

I’m not sure what more details I should provide. The phones are Polycomm SoundPoint IP. The server has 2 zaptel cards 8 ports each with 16 phone lines going in total. I am not sure how many calls this server can handle at a time(If one line = one call either way ) or (multiple calls per line).

Any help is appreciate. THANKS!

Centos 5.2 (final) 32 bit kernel: 2.6.18-92.1.22.e15
Asterisk Source Version:
Zaptel Source Version:
LibPri Source Version: 1.4.9
Addons Source Version: 1.4.7
PBX in a Flash Version 1.4 Daemon
Free PBX
PIAF Daemon 1.4

Does the phone ring or is the outbound call being placed and they are connected with a caller coming in your analog lines.

With analog lines their is a issue called glare or collision. Basically a outbound call gets placed at the same time a call is coming in but Asterisk is not aware of the incoming call yet.

Their is no 100% way to fix this with analog lines. Best setup is to change your trunk to use G0 instead of g0. The big G tells it to start at the highest channel number on outbound calls instead of the lowest channel number to minimize the collisions.

I am pretty sure that there is no ring, it just connects to the incoming call. Regarding the G0/g0, in FreePBX where is that change made via the GUI?
Why would this change help? Is it because inbound calls come in on low numbered channels first so we are minimizing the problem?


Yes your carrier sends calls starting with channel 1. By you starting outbound calls at channel 16 the chances of glare are drastically reduced.

You set it in the trunk page in the GUI at the bottom of the page. It should say g0 right now.

One more thing. You must be absolutely sure that you have plugged your phone lines into the card in the correct order. Line one in the incoming hunt group goes to channel 1 on your card, 2, etc. If they’re plugged in at random, changing g to G won’t matter.