SIP protocol For consumer or family use 1 FXS port, 1 Line (Can use for PSTN in and out to PSTN) port Ethernet ports: TWO* 10 Base-T Ethernet ports, HUB function Functions: Out route selection(use VoIP or PSTN), Caller ID transfer(VoIP and PSTN) Impedance: 600 178x 119x 31.6mm (L x W x H)