At 11:30 15.01.97 +0000, you wrote:
>Sensibly, he now opts to use a redundant PC (XT or AT) and the 8-bit
>analogue game port available on many cheap combo cards.

To my knowledge, the game-port of a PC is NOT an A/D-converter, but
only something like a variable frequency generator.
Thus, it can only sense variable resistors on both channels, and
you cannot measure a voltage.

So, might be easier to use a PIC16C71 with software RS-232.

regards, 
Wolfram


+-----------------------------------------------------+
| Wolfram Liebchen                                    |
| Forschungsinstitut fŸr Optik, TŸbingen, Deutschland |
| mailto:liebchen@ffo.fgan.de                         |
+-----------------------------------------------------+