GSM FWT-360 is a GSM to Analog Converter (dual ports, insert 2 sim cards), the device can produce a FXS line to allow a regular phone to be connected and used just like a local landline(PSTN) except your calls will go out the GSM network. This device can both receive and make calls.
Please be noted that 2 SIM cards are independent with 2 modules inside, if 2 calls reach 2 SIM cards at the same time, both calls could be answered.
The main application is:
Connecting the RJ-11 FXS line to connect Ordinary telephone set for voice call,
to connect PBX for call extentions,
to connect billing systems for public phone use,
to connect VoIP gateway to realize VoIP call termination,
to connect alarm system for security purpose, etc.
It is not a VOIP gateway, nor a GSM+VOIP gateway,.
It is a GSM Fixed Wireless Terminal that produces a Analog FXS phone line.