A multi-functional gateway that aids in efficiently implementing communications between 2G/3G mobile networks and VoIP networks is Dinstar UC2000-VG-32G 32 Port GSM VoIP Gateway. Users can change SIM cards without disassembling equipment thanks to a newly designed pop-up SIM card slot. The users might also create their own application software to send SMS/USSD messages or bulk SMS messages, or push their text messages through email, HTTP, etc. with the open API. It has an excellent performance in software features and also in the new hardware structure design. The gateway provides low-cost, easy, and flexible IP telephony solutions to enterprises, SMEs, business offices, etc.