Martin H. Eastburn wrote:
What airhead or terrorist allowed or put that in. Might be a plant.
There are mistakes, but that kind of stuff is normally protected better.

This was all WAY before 9/11, of course.
Weird stuff happens, like when a certain R&D center published the keypad
concept for not only home phones but the extra set for trunk and
stations...

Bell System Technical Journal, usually totally impenetrable
jargon-filled stuff on statistical modelling of phone system
traffic, but it had a complete and detailed description of STMF
or in-band signalling before the group 7 phone exchanges went
live and moved to out-of-band signalling. Nobody needed the
keypads, a guy I knew specifically used pieces of audio tape
with the right tones on them, and spliced the tape with the
right length to get the right timing. If caught, he carried a
strong magnet to erase the thing. Kind of "Mission Impossible".
There was a blind guy at MIT who could do it by whistling!
That mistake into a company magazine - went to university libraries around
the country and soon the birth of the black and blue boxes that dialed
free long distance calls.

it wasn't a mistake to put the info there, but it was a bit of a
mistake to underestimate the capability of the early teenage
hacker/anarchist crowd.
In the late 60's and early 70's those were a rave - and pay phones on
college
campuses were taken out as they were simple targets. Now cell phones
make it
easy enough to call away.
Did you know you could wire in a switch into the phone wire to
those old pay phones that would disable the "drop coins into
coin box" signal that was sent from the phone exchange when the
called party answered? I actually found one of these on a pay
phone at the university years ago.

Jon