There is a lot to be said about GSM solutions with Elastix. Looking at Elastix's Certified Hardware web page, we notice that there are a lot of companies that provide the devices and features to connect Elastix to GSM networks. Elastix even launched a couple of GSM Gateways. GSM Gateways enhance Elastix's capabilities by integrating mobile services with our IP-PBX having the following applications:
GSM connectivity for IP-PBX
Mobile PBX
GSM VoIP gateway
GSM callback services
SMS services (inbound/outbound)
These devices require the physical installation of a telephony card to support the SIM cards. In most cases, the GSM Gateways use an SIP trunk between them and our Elastix Unified Communications Server. In this recipe, we will focus on the procedure needed to set up a GSM Gateway with an SIP trunk and Elastix.