The handset looks like a regular mobile phone, but has a Compact Flash card slot on the back into which the user can plug a networking card for either wireless LAN or PHS.
"This is the first in a new style of mobile telephone," said developer Kazuyoshi Kojima of Mitsubishi's silicon devices technology department. "If you want to change the network, you just pull out one card and plug in another," he said.
Such a design has some advantages for mobile telephone makers. Because the radio portion of the telephone is in a plug-in card and not part of the handset, manufacturers will be able to put the handsets on sale in almost any country and avoid the time-consuming and expensive radio frequency testing required by regulatory authorities in most countries. The cards will still need to be approved, but many are already available.
Coupled with an IP telephony service provider, the phone could, in theory, be used anywhere in the world in which a wireless LAN connection to the Internet is available.
Mitsubishi hopes to launch the mobile phone in 2004.