Thanks to :

* Rachel J. Smith for lending me her calculator so I could check the
  voltages used by the fx-7700GB to communicate.
* Mike Cook (of Acorn Computing (formerly The Micro User) fame) for
  expert advice on how to convert to and from TTL RS232C to RS432 and
  for info on reading and writing the serial port under RISC OS 3.
* Dr. Gary Greene and all at the Physiology dept. at the University of
  Newcastle-upon-Tyne for lending me a 'scope and their time.
* Andrew Ward for giving me the OS_SerialOp details all neatly typed
  out for me.
* Bob Parish for giving me a copy of the protocol which he figured out
  when he was horrified at the cost of the PC link hardware and
  software. I can supply his program and construction details on
  request.
* Graeme Barnett for lending me his PRMs occasionally.