"luke.leighton" luke.leighton@gmail.com writes: ...
instead, the spec therefore has to reflect that and require that the I/O boards add in suitable compensating circuitry instead. none of the I/O boards have gone into production yet, so that's the only remaining place where the flexibility and changes can go.
It strikes me that the I/O board is actually the right place for that protective circuitry anyway.
Putting such circuitry on the CPU card consumes space where space is at a premium, and for applications where the RS232 is superfluous, you would be forced to pay for components you don't need.
Now that it's defined as going on the I/O board, people that don't need RS232 can simply leave those pins unconnected and they'll have fulfilled the requirements to protect the pin from power.
Cheers, Phil.
P.S. It just occurred to me that even where it had been decided not to bother with RS232 on a device, if one discovered a need to access it one could have a pass-through board that would stick out of the side of the device, and have a socket for a CPU card, and expose the RS232 lines (via relevant protection as per standard), with all other connections going to the PCMCIA plug at the other end of the card.