Specification 
Support SIP 2.0 (RFC 3261) Protocol
2 RJ45 Ports, 10 Base-T (WAN/LAN)
2 RJ11 Ports
FXS, Analog Phone Port
FXO, PSTN-to-VoIP or VoIP-to-PSTN Call Forwarding
PSTN Pass-Through Function
Built-in DHCP/NAT Router
Codecs: G..711, G.723.1, G.726, G.728, G.729A/B

 Function 
Caller ID/Display or Block
Call Forward
Call Transfer
Call Hold
Call Waiting
3-way Conference