The USB Phone is voice comunication terminals over the internet. It is a different way of comunication from traditional telephones. It connects directly to PC through the USB port. With DSP chipset set inside. its sound is very clear. PC to PC is free of charge. You can make calls from PC to regular phone when the internet is connected with PSTN network by gateway. It can work with cable and Dial-up internet, Broadband and LAN connections.It is especially suitable for those who make long-distance calls frequently. Easy to use, easy to set up. The best of all,it saves money   Functions: PC to PC, and PC to Phone dialing capabilities Easy to install USB plug and play Trimline and fashion design Kaypad dialing Full duplex audio, echo cancellation Compatible with all popular VoIp soft service such as Bitcall,Netmeeting,MSN,Netphone PC sound card not required Attachment for a headphone port, easy to listen to HAD handset and operate as a traditional telephone High mobility with workplace   Electric Parameter: Conformity to USB Audio Device Release 1.0 Conformity to USB HID version 1.0 Valtage:4.5-5.25V DC   The network system requiry: CPU: Pentium200/64MB Ram/100MB Operation system: Microsoft Windows98/SE/ME/2000/XP Internet Condition: LAN, Cable Modem, XDSL, ISDN, or Dial-up Modem