Axon, axoff

riend of mine poses an interesting question on his blog:

n most of the equipment I work with, the sensors (RTD’s - heat sensors that tell the controller the temperature of something, photocells – proximity sensors that sense when the product, ie., a box, is passing a certain point on a conveyor, limit switches – simple mechanical open/close switches that would tell the controller a safety door was open or a button was being pushed) each typically communicate with the controller through it’s own pair of wires that go from the sensor to an input/output board in the controller. You can end up with a lot of wires.

Now there are systems that use control networks and “smart sensors” that not only send the information for which it exists (“115 ohms meaning 350 degrees F”, “I sense a box!”, or “button pushed”) but also a packet of info identifying the sensor. This way, you can run all this information through a single cable instead of hundreds of wire pairs.

My question is… in which way does the human body work? The first (dumb open/close switches) or the second (smart sensors)?

His guess that it’s the second option (his initial guess at least). My guess was the first. Wikipedia talks of nerve cells but I can’t seem to find a smoking gun. Opinions?