--On Wednesday, January 02, 2013 13:34 -0800
ned+ietf@xxxxxxxxxxxxxxxxx wrote:
>> > From: John Day <jeanjour@xxxxxxxxxxx>
>
>> > I remember when a modem came with an 'acoustic coupler'
>> > because connecting it directly to the phone line was
>> > illegal. 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.
>> > ...
>> > It may have been illegal in some countries but
>> > certainly not in the US.
>
>> Huh? Remember the Carterphone decision?
>
> Absolutely. Too bad the FCC didn't see fit to extend it to
> wireless.
>...
> At one point there was something that said one phone in each
> home had to be directly wired without a plug. I don't know if
> this was a regulation, a phone company rule, or just a
> suggestion, but it also fell by the wayside after Carterphone.
IIR regulation, in many states even for a while
post-Carterphone, and justified, again IIR -- as many things
have been justified in more recent years-- on the grounds of
emergency services applications. After all, if there were an
emergency, you wouldn't want to go hunting for an unplugged
phone or, especially, to get something working that required
external (to the phone system) power.
And, while my memory of the period is a little vague at this
point, I'm pretty sure that the four-pin jack (and a few other
proprietary terminal-device connectors) showed up
pre-Carterphone, when AT&T/WE was (i) trying to sell alternate
phones (notably the early "Princess") to prove that what became
Carterphone wasn't necessary because they could meet the
relevant market demands and (ii) arguing that, if one wanted to
connect third-party equipment, they could supply a network
protection device into which the third-party stuff could plug.
RJ11 and friends came along when the FCC finally got rid of the
protective device/coupler nonsense in the mid-70s, long after
Carterphone (1968) and, in a series of steps that weren't
complete until the last half of the 90s, regulated/required
first the jacks then the wiring pinouts.
> I certainly saw acoustic coupled equipment in use long after
> Carterphone, but in my experience it was because of general
> intertia/unwillingness to do the necessary engineering, not
> because of the lack of connectors.
My recollection is that acoustic couplers started out as an
attempt to get around the protective device rules, not the "no
interconnection" one. It that is correct, it would provide an
additional explanation for their being around into at least the
mid-70s. I think part of what killed them was the growth of
different handset shapes along with multiple manufacturers of
telephones. Those different shapes meant that one could no
longer design a recessed-cup device with fixed spread between
the two cups that would form a tight seal with all relevant
handset shapes. I do have an acoustic coupling device from the
mid-90s that had an adjustable distance between the receiving
and sending attachments and a strap to attach it to the phone --
worked pretty well when one wanted to attach a modem in, e.g., a
hotel with hardwired connections between phone and wall and
setups that made pulling off the terminal cover and attaching
alligator clips impractical but it is clearly an exception to
Ned's suggestion that failure to make the transition was at
least partially due to unwillingness to do new engineering/
design work.
The situation in other countries was, of course, different.
Especially in places where the telephone carrier was effectively
its own regulator or managed to convince the regulators that
content mattered as much or more than physical connections,
there was a requirement for different jacks (usually at a higher
monthly rate) for modems and fax machines than was used for
voice. I believe that particular approach survived and may have
been reinforced by efforts to promote deregulation within ITU
because the relevant carriers argued that the early deregulation
efforts applied only to POTS service and not to "data" ones.
That approach and position was contemporaneous with national
regulations in many countries that one could run all of the
TCP/IP services one wanted as long as they were run over the
national X.25 profile and sometimes as long as one claimed they
were "transitional" until OSI Connection-mode stabilized.
There might be a useful lesson or two in that bit of history.
john