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Re: Acoustic couplers

2013-01-03 09:23:28


--On Thursday, January 03, 2013 06:52 -0800 Dave Crocker
<dhc(_at_)dcrocker(_dot_)net> wrote:

...
A line mod was probably against the rules irrespective of
Carterphone in those
days. But had you bought your own phone with a ringer switch
and hooked that

Not allowed at that point.  All user equipment that was wired
to the system had to come from the phone company in L.A.

And, if you intended to get around "wired to" by using a
(proprietary) jack that jack had to be installed by the phone
company and they could charge just about anything they liked for
that.

More important, I think that had you checked carefully and
mentioned "Carterphone" a few times (the information was rarely
if ever volunteered), you would have been told that of course
you could connect a third-party phone.  In Pac Bell's area, you
either had to do it via a Pac Bell-supplied network protection
device or the phone had to be AT&T/WG tested and certified to
not cause damage to the network.  The monthly price for the
protection device and the cost of certification were high enough
to make using (or manufacturing and selling) third-party
equipment implausible for any conventional endpoint application,
but the option was there in principle.    I don't know what the
situation was in GTE's area, but assume it was similar.  

Carterphone was a huge step forward, but the device itself was
acoustically connected and the decision did not open up the
possibility of connecting uncertified third-party equipment to
the PSTN (jacks or otherwise).   Many of the effects we now
depend on were not really available until the FCC abolished the
right of the the carriers to require protective devices that
they controlled and the MFJ broke the close link between the
design and manufacturing organization and the standards-setting
("system practices") one (and started to really open up
inter-carrier interconnects).  Those events didn't occur until
the last half of the 70s and first half of the 80s.

best,
    john

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