>> OK, so if I'm understanding this right... The 74126 (go look it up) 
>> contains 4 "buffers" - gates who's output is logically equal to their 
>> input. But each gate also has an "enable" pin. When the enable pin is 
>> high, the gate works like normal. When the enable pin goes low, it's 
>> like the output pin isn't connected to anything any more.
> 
> Yes exactly.
> 
>> And it seems that this allows you to connect several outputs together, 
>> forming a kind of wired-OR configuration, provided that at all times 
>> only one gate is "enabled".
> 
> Yep, you could make a simple address decoder logic circuit (ie have a 2 
> bit binary input to select which of the 4 buffers to enable) - that way 
> you would guarantee only 1 would be active at a time.  If you were to 
> connect a 2-bit counter to the 2-bit address lines you would then have a 
> 4-bit parallel to serial converter :-)

I was thinking more about routing bundles of signals from place to 
place. The "obvious" thing to do is use logic gates to combine the 
signals, but I guess using these weird 3-state systems allows you to 
save a few logic gates (and hence ICs, wiring, and ripple time).

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