I have configured my asterisk with freepbx. The cell calls are routed through a sip-gsp gateway with one channel, so I set to 1 the parameter maximum channels in the trunk, if this is busy the next cell call is router with a sip provider.
Now I want to use the sip-gsm gateway for incomming calls to. The problem is:
When an incomming call is in progress and I want to make an outbound gsm call asterisk detect the gsm trunk is busy but is not routing the call vis the sip provider, the call is hanged up.
The problem is related with the maximum incomming calls the parameter is not present in freepbx,