One Touch Call Button SIP video door phone solution is to control the visitor access through video screen which can be installed at the entrance with internet connection. One Touch Call Button IP Video door phone (AP-VAC50N, AP-VAC20N) uses SIP standard VoIP signaling process function to interwork with AddPac video door phone access control server (AP-ACS1000, IP-PBX + Control Server), SIP video phone, and SIP soft phone to provide an excellent scalability. Also, it supports the latest audio/video codec at optimum level. SIP video door phone selection is to accept the VoIP standard signal and convenience. AP-ACS1000 Door Access Control System offers the enterprise level IP video access solution.