Features: 1) Supports Skype, MSN, net2phone, Stanaphone, SJphone, X-Lite, X-PRO, Firefly, Xten, eyebeam, ICQPhone, Yahoo Call Center, etalk, AIM Phone, and Baoshitong softwares 2) Supports SIP, H.323, MGCP, IAX2, net2phone protocols 3) USB 2.0 port 4) 16 bit sound card inside, the PC can be without sound card 5) Supports product serial write in 6) With HID (Human Interface Device) feature 7) Plug and play to install USB driver 8) No driver needed for Win98 SE/Win ME/ Win 2000/Win XP/Mac OS/Mac OS X 9) With PID (Physical Interface Device) feature 10) Implements Real-Time verification 11) Compatible with major PC\'\'s Internet phone application software 12) Provides ringer generation for PC to PC call through existing IP phone applications 13) Optional ITSP application software with credit for PC to phone connection 14) A LED to indicate power and linking status 15) Adjustable volume for handset 16) Supports E.164 dialing rule 17) Record support 18) The powered via the USB port without need for a power adaptor