I have a problem where I need to both set and monitor approximately 16 digital line states through a cable about 3m long. Ideally I'd like to have parallel signals at both ends, but serialised for the cable. i.e. parallel - serial ---- cable ---- serial - parallel. Any signal at the parallel inputs on either end should be replicated on the other. The rate of update doesn't have to be high, even 1Hz would be fine. I can't seem to find a pair of parallel to serial and serial to parallel ic's to simply do this. Also SERDES devices are typically for much higher speeds than I need.
Does anyone know of a convenient way to do this?