Sean - Interesting information and approach by COCO
How CoCo works: The software sits on top of existing networks and acts like a conference call, allowing individuals and other networks to connect. "The CoCo protocol is the fabric that sews it altogether," said Peter Erickson, vice president of business development.
In practice: With the software, a handheld device equipped with only a wireless Internet chip can act like a walkie-talkie and communicate with UHF or VHF radios. The device can also connect to a wireless Internet access point and view video. It can also make phone calls without a cellular connection. The only requirement is that it is in line of sight with another device using CoCo. See weblink:
http://seattletimes.nwsource.com/html/b ... ace06.html
Here are some other interoperability products
1) Motorola Motobridge used in State of Florida for state interoperability.
http://sion.motorola.com/pages.aspx?pag ... escription
2)Cisco IPIC rsystem with routers
http://www.networkworld.com/news/2005/1 ... radio.html
3)the interoperable switch by Raytheon
http://www.jps.com/index.asp?node=118