The design of the Fanvil i20S SIP Door Phone is based on experience and knowledge of Fanvil IP phone developments. The Fanvil i20S use standard IP/RTP/RTSP protocol for voice transmission and enjoy the advantages of full range of compatibility. The Fanvil i20S has a variety of enterprise-level features and is compatible with lots of major platforms, such as 3CX, Asterisk, Broadsoft, Elastix, etc. The Fanvil i20S SIP door phone is designed for operation in indoor conditions. The robust mechanical construction offers protective coverage rating against dust and water (IP54). The i20S is economical devices with triple function(All in 1)- Access control by call, code and RFID card