This is a two-in-one phone, which allows VoIP as well as normal PSTN phone calls. For VoIP calls, it uses both SIP (Session Initialization Protocol) and H.232 protocols. It doesn't require a PC with a modem to make VoIP calls. It has a built-in modem to connect to the Internet-all you need are an Internet account from an ISP and a VoIP Internet telephony account from a service provider such as VSNL, IPYantra and Net4India. You need to enter the ISP and VoIP account details into the phone through the interactive voice-response system driven menu on the phone. To make a VoIP call, press a dial-up button on the phone, which dials into the ISP and gets your Internet connection up. An LED and voice indicator inform you when this connection is complete, after which you can make calls to any local, STD or ISD number. The phone supports hands-free dialing and re-tries many times and rings back when the called party answers the call, though you need to use the handset to talk to the other party.
You can also receive Internet calls if you have that service from your VoIP provider. We tested the phone with a Sify ISP and IPYantra VoIP account. It connected very fast and the voice was very clear with no noticeable jitter. But keep in mind that the voice quality is also a function of the quality of your Net connection.
The Bottom Line: If you're looking for a reasonably priced option for making long-distance calls, this phone is worth considering.