GSM and PSTN gateway for asterisk EPBX

This paper intends to describe the voice and video calling on mobile phones and PCs´, as well as the GSM integration with asterisk PBX server. The clients can register on the asterisk server through mobile phones or PCs´. The devices should be connected to the server via wireless or wired LAN. The registered clients can make free voice and video calls to communicate among themselves. The clients can call among themselves even if they are registered on two different asterisk servers, if the servers are connected through IAX protocol. The gateway is used to route VoIP calls on to the PSTN network (GSM as well as landline) and vice-versa. 4-port FXO/FXS card is used for implementing PSTN gateway while a Bluetooth enabled mobile phone compatible with asterisk server is used to implement the GSM gateway. This model will drastically reduce the overall cost of communication.