29 Jun
2007
29 Jun
'07
3:20 p.m.
Doesn anyone still have the do-it-yourself modem from Popular
Electronics, called the "Pennywhistle"?
I rememebr the 'build your own modem for under $50' article in Byte
(Circuit Cellar, of course).
I also well rememebr the Maplin Modem (a build-it-yourself 300 baud
direct connect unit). It used a 14412 for transmit, but they apparently
couldn't get it to demodulate CCITT tones reliably, so they added a
separate PLL chip for that (XR2211 or something like that).
I may still have a couple of brand new, unpopulated, PCBs for this
project somewhere.
-tony