Fanvil i20S is a network-enabled intercom with built-in 125 kHz RFID card reader for simple, secure access control and door entry. Fanvil i20S runs the open SIP protocol, which means you can have broad choice of VoIP platforms to use, including 3CX, BroadSoft, Asterisk, Xorcom, and Huawei. Running SIP makes i20S easier to manage than traditional door phones. The full-duplex intercom gives you wideband audio for easier to understand calls.