... & USSD 1/4/8/16 ports gsm voip gateway,wireless voip gateway VoIP GSM Gateway GoIP bridges the GSM and ... enabling voice communications. It is installed on the Mobile SIM Card, you can register the GSM telephone on the VoIP ... are 7 models.GoIP-1 ( supporting one SIM card ), GoIP-1i ( supporting 1SIM card, built-in antenna)GoIP-4( supporting 4 ... runs. 1/4/8/16 ports gsm voip gateway,wireless voip gateway