bapu
Sharke, they were called acoustic couplers. I was using them in 1978 to dial into our HP3000 at the office so I could work from home in the evenings.

The first computer time-share I was part of (1971) was an HP2000 and it also used an acoustic coupler.  By 1976 we had one that was more advanced that could do 110 and 300 BAUD.  If I whistled into the phone at exactly 4,800 Hz, you could hear it jump up in tone then we'd quickly slam it into the coupler and hit the <Return> and <Line Feed> keys alternatively (the acknowledgement sequence) until it connected.
 
How's THAT for some old geekiness!
 
Oh yeah, public pay phones had a similar trick to them where you could whistle at exactly 4,800 Hz and get a dial tone without putting any money into it.

Apparently there's an auto shop in Poland which is still being run on a C64.

http://sploid.gizmodo.com...d-to-run-an-1787196319

sharke
Apparently there's an auto shop in Poland which is still being run on a C64.

http://sploid.gizmodo.com...d-to-run-an-1787196319

In way out places, I would imagine that there are many folks running some really old stuff. My ol'e roommate was able to get many of these old things working, though not necessarily on the same chassis. And nowadays, he is restoring X-Box'es for fun!