Gents;

Your suggestions thus far have been very good pointers on the issue,
much appreciated.

To clarify, the task at hand is not to reverse engineer the software or
even the hardware ( I would not feel comfortable reverse engineering
one's software) but studying the message format on the communications
link between the devices.  It is a situation very analogous to the TV
remote control debate.  You can make a reciever, then study the message
format, and make your own transmitter.  But is this (A) legal, and (B)
ethical?  I have made the argument in the past that if one were to make
a nockoff remote, and then market it, that if it were to exibit poor
performance, then that product might make the manufacturer of the TV
look bad, and that they had a compelling reason (but not a legal
right??) to restrict third party devices that work on their TV.  I
obviously painted myself into a solid corner.

Any further ideas?  Such as case law on one manufacturer studying
another's product?

Thanks
Chris Eddy