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Museum of Communications
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The third floor of the Museum of
Communications houses telephone switching equipment, old teletype
equipment, and other old artifacts. The following is a picture gallery
of the third floor. <- Go back to Third Floor Page 1
Look at all the cabling inside all those racks!
To the left of the picture is the #1XB test board.
The Direct Current Power Board. How are you able to
control the electrical power required for a large central office? Very
carefully! At 48 volts DC and over 1000 amps, this system controls the
power board for adding additional batteries when the main AC power
goes out, without short circuiting the system while batteries are
added or removed, or adding or removing the emergency generator from
the system.
Go to the Second Floor - Page 1 ->
Copyright 2008 Telephone World |
Magnetic
recording technology has been around for a number of years. The first
practical uses were magnetic wire recorders.
Here’s
a reel-to-reel magnetic tape recorder. Modern tape recording was
invented shortly after World War II
Please
leave your message after the tone.. tone… tone.. tone. This is an
early answering machine (Western Electric made, of course). The
outgoing message was on a 45 RPM record, the incoming message on
magnetic tape.
This
is also from the “you’ll never know what you’ll find” department. This
is a poster for Alascom, which was at one time the name of the largest
telephone company in Alaska. Since this time, Alascom has been bought
out at least two or three times.
Underwater
cables have been a challenge for many years. Here are some early
examples of how telephone engineers of yesteryear were able to meet
the challenge.
Old
computers and radios. Hey Bruce – is your old CB radio in this
stack?
Can
you wash me now? Again, Western Electric branched out and even did
home appliances. This is an old washing machine from around 1920.
Can
you hear me now? Now? And again? Here’s an old hearing test kit that
used phonograph records to create the tones, instead of
electronically.
Nooooooo!
A sign for the (then) forthcoming 5ESS switch. Basically the bread and
butter digital end office switch that Western Electric introduced in
1982 and Lucent still makes to this day.
Before
the invention of the photoelectric cell and films with emebedded
soundtracks, here’s an experimental soultion – using a phonograph
record with a projector. I’m not sure how they were synchronized, if
at all.
FINALLY
– the telephone switches. Unfortunately, I didn’t take any pictures of
the Number 1 Crossbar (#1XB) or Panel, but I took a number of pictures
of the Number 5 Crossbar (#5XB).
Relays
associated with the #5XB switch.
The
relays associated with the incoming register.
A
sign that helps describe the #5XB switch and a Touch-Tone to frequency
conversion table. (where was the sign for multi-frequency tone
conversion'')
More
Relays!
Here’s
the test board for the #5XB. I made a few calls from here to the #1XB
and Panel switches.
A
small cord board operator station.
An
emergency phone for use by the police. This was used before there were
radios in police cars.