... 1; USB ports:1 Host;Extension Amount: 50 VOIP PBX with 4 FXO port, 50 users(MSQ-50B) Network ports: 2 10 ... 1000mATemperature: 0-40Humidity: 10%-90%RH, anti-caking Work under the following protocolSIP agenc/login/location/severRFC3261 (RFC3262, 3263, 3265, ... answer for phone exchangeAuto beep answer for phone exchangeCall restriction(Music on Hold),coloring beep(phone exchange beep)Calling record check ...