Four years ago, Calypso Wireless got a certain amount of attention with its bid to tax everyone's fixed-mobile convergence. Apparently, it hasn't gone away - and now it has European patents.

In 2004, Calypso Wireless claimed that its US Patent 6,680,923 covered all roaming between wide-area and wireless LAN - and was in effect a patent on all fixed-mobile convergence.

The company talked about a technology in the field called ASNAP, and subsequently issued press releases and announced sales for a C1250i dual-mode handset. The company's site also claims a VoIP client for the iPhone. We've not had any response to our request for more information on the iPhone client or the earlier product. And in any case there are plenty of iPhone VoIP clients available, from Truphone and others

We're not patent experts, but Calypso's looked very non-technical to us - and we believe in 2004 there was prior art. Still Calypso's president Richard Pattin believes "In plain English, any carrier that wishes to provide its customers with a cell phone that automatically detects any available WLANs and then seamlessly switches between the standard cellular link towers and available short-range broadband network, such as cable or DSL Wi-Fi, must sign a license agreement with Calypso Wireless."

As far as we know, no companies have publicly signed up - although at one stage it promised an unnammed network operator was trying it out, in Calypso's native Florida. The stock price peaked at about $4 in 2004, and is now round about zero, andthe biggest activity has been on Investors Hub, where investors are audibly crossing their fingers.

Except the company now says it has registered its patent in 25 European countries.