I have set a SIP extension and a custom trunk associated with my GSM modem.
I think both SIP extension and trunk are working, because I am able to connect to the SIP extension with a SIP Softphone and the trunk, when I make a call to the GSM number, I see on asterisk’s log that it “saw” the call but it doesn’t have anywhere to forward the call.
1- Created a new trunk with this settings (other settings not changed from default):
Trunk Name: timfixo
Outbound CallerID: full gsm line number (equaly as I had specified on install-dongle)
Maximum Channels: 1
Custom Dial String: dongle/dongle0/$OUTNUM$
2- Submit and Apply
3- Create one or more extensions. I’ve used:
Device = Generic SIP Devie
User extension = 1000 (extension number - this is your user on SIP client)
Display name = casa
secret = password (you password on SIP client)
4- Submit and apply
5- Create inbound route
Set Destination - Extensions = 1000
6- Submit and apply
7- Create outbound route
Trunk Sequence fo Matched Routes: 0 = timfixo (your trunk name)
8- Submit and apply
After this I can use any SIP client to make and receive calls from GSM line. In my case I’m using an old WRTP54G router that has 2 FXS ports as client. On it I’ve connected a fixed landline phone.