Personal Telco in Portland, Ore., has set up the first voice over IP over free wireless hotspot: We think this is a first, and they think it's a first. The story says "for the price of a latte"--implying a purchase, which we believe isn't necessary--you can make free VoIP calls. The VoIP unit is plugged into a PC which is connected wirelessly to the Internet, PersonalTelco guru Nigel Ballard confirmed for me via email.
Ballard said the VoIP adapter uses a virtual line from IPKall, which offers a free public switched telephone network (PSTN) number in the 360 (southern Washington state) area code. Incoming calls, outgoing 360 calls, and 1-800 number calls are all possible, as well as SIP-to-SIP. (SIP numbers aren't six digits; this is erroneously noted in the article.) The next goal is setting up a local 503 node, Ballard said.
The article conflates a few concepts into SIP. Session Initiation Protocol governs the connection. To quote from the IETF proposal for codifying it, SIP is a protocol for initiating interactive communication sessions between users. The writer conflates codecs (compression/decompression routines) used to encode and decode sound (and/or video) and the issues of bandwidth and latency with the actual connection method.