SOHO IP-PBX with POTS, GSM and VoIP Connectivity,Built-in Ports: ,4 CO and 16 Single Line Telephone Ports,Optional Interfaces:,VoIP Server, GSM, Voice Mail,Power Supply: ,External Adaptor - 24VDC, 1.5A,Key Differentiators:,16 SIP Extensions, 8 SIP Trunks, Mobile Extensions, etc.