From: John Day <jeanjour(_at_)comcast(_dot_)net>
No, there was nothing illegal about it. The reason for acoustic
couplers was that the RJ-11 had been invented yet and it was a pain
to unscrew the box on the wall and re-wire every time you wanted to
connect.
In the 1970s, in the US, and for inter-state use, you either had to
rent the modem from the phone company, or rent a "data-access
arrangement" device to connect your modem to the network. The DAA
cost about as much as the modem, so there was little in the way of
independent modems. Acoustic couplers got around that rule.
Also, in those days, there was a large four-pronged plug that could be
used for phones. It was sometimes used when people wanted to move
phones around. http://en.wikipedia.org/wiki/File:4prongplug.JPG
Dale
