We currently have an existing PBX system in our office which we’ve been unsuccessfully trying to expand.
At the moment this PBX system uses a external VOIP provider for outbound calls, and ISDN for incoming.
What we wanted to achieve was that outbound calls to mobile telephone numbers would travel out using a SIP to GSM gateway, and the landline calls would continue using the existing VOIP provider.
It turns out however that our existing PBX cannot connect to multiple SIP trunks at once, so we cant have it connected to both the GSM gateway and the main voip provider at the same time.
What i’m hoping is i can slot asterisk in between the two. I know asterisk can happily handle multiple trunks and has plenty options for routing the outbound calls to the appropriate trunk.
What i’m unsure about is how i setup Asterisk to act AS a trunk for the existing phone system, or what this mode of operation would be called.
Any tips or pointers on how to go about this would be much appreciated.