Basic GSM gateway


I’m using a supported dongle on a Raspberry PI and I’m using asterisk and FreePBX to develop a GSM gateway for me.

I allready have one SIP account that I can login with success.
I would like now to make outgoing calls to be routed to the 3G dongle.

Is there a basic howto for that? This is the first time I’m using this.

PS: I allready activated voice in the 3G dongle. :slight_smile:


I’m trying to do the same as eluis.

I have a Raspberry Pi running FreePBX distro.

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.


Ok, I got it to work.

What I did:

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.



Thank you very much Renato…
It seems simple. I’m having some problems with SIM registering into the network.

Obrigado Renato,
Parece ser muito simples.
O meu problema agora parece ser com o registo do cartão SIM no operador. Ainda estou a ver o que se passa.

Link aqui:

hi i did jut the way you descrived but i can receive calls but i can’t make outbound calls.
can you help me?

Boa tarde,
eu fiz tudo como desceveu mas eu naão consigo fazer chamadas para fora.
recebo mas nao faço.
eu sou português por isso pode responder em português.