January 2007: The HeyPhone documentation on this site derives, for the most part, from material produced during the period 2002-2004. Although still largely correct, documentation may go out-of-date with respect to corrections, obsolete components, updated techniques and peripheral apparatus.

Occasionally, updates to this web site may be produced but, as time goes on, this will become less likely. To find out the current status of the project you should subscribe to the HeyPhone discussion forum where you can share your requests and experiences with the wider caving community (assuming, of course, that it reads the forum).

Please note: the HeyPhone project is not actively supported by CREG. CREG has no brochures, no circuit boards, no components and no built units for sale. The HeyPhone is entirely a "build-it-yourself" project. The only support available is the documentation on this web site, and any "public" help you may receive in response to posting a message to the HeyPhone discussion forum.