I am wondering, how does my keyboard manage with 5 wires?It must be encoding input in some way, say two is power supply, and three is output.
-- Dimitris Tzortzakakis,Iraklion Crete,Greece major in electrical engineering-freelance electrician FH von Iraklion-Kreta, freiberuflicher Elektriker dimtzort AT otenet DOT gr
A PC keyboard I presume you refer to?
The signal is carried on one line and serially encoded. It is actually bi-directional because the computer tells the keyboard to turn on/off the caps lock and other LEDs. The keyboard doesn't decide to do this itself -- if the computer hangs such that the keyboard interrupt routine isn't being called, you'll find CAPS-LOCK stops toggling the Caps LED, which can be useful to see at how low a level a PC is hung. A second line is the clock for the serial data.
You can find the pin-out here:
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