hay ... @alumni.uark.edu (Jim Haynes) wrote
> Every manual switchboard I've seen, from PBX to central office, has an
> audible alarm that the operator can turn on or off. When turned on it
Sounds when there is an incoming call that needs attention. It also
lights a signal lamp on the board. This circuit is always called a
The typical manual switchboard "audible alarm" was a buzzer. Bell
System PBX buzzers tended to make a rapid clicking sound rather than a
buzzer, that sound was a bit more pleasant.
In service, busy switchboards kept the buzzer off and operators
watched for signal lights, both on the jackface as well as supervisory
signals from cordpairs. In light service, where operators would be
doing other tasks, the buzzer was kept on.
The "night alarm", if present, was a separate loud bell, intended to
someone from a distance or wake someone up.
Cord PBXs had "night connections". When the switchboard was shut down
for the down, connections would be made with outside trunks and
designated extensions to receive calls. Modern (1960) cordless dial
PBXs had a more sophisticated system: after hours a separate bell (old
style wall mounted bell boxes) would sound. Anyone who wanted to
answer would dial a special code and would get connected to the
incoming outside call.
In the Moutain Bell history, "Muttering Machines to Laser Beams", they
describe in detail life with a home switchboard. The telephone
company inspected the home very carefully, down to how clothing was
arranged to bureau drawers. My impression was that service WAS
available 24/7, late at night the alarm would wake the operator up.
In the small communities there would normally be very little night
traffic, but people would need to call the doctor or report a fire.
During WW II, a long distance call from a hometown serviceman might
In my own town, the local switchboard serving a few hundred lines, had
two positions with a full time operator and a part time assistant.
(The assistant was in high school at the time and still lives in town,
and kindly shared her experiences with me*.) Anyway, the switchboard
was in a private home; my point being even a busy two position board
could be in a house.
During ESS trials, the lab men considered "taking over" the switch
late at night which meant taking the exchange out of service. A few
minutes before the shutdown an emergency call for a doctor came
through. They realized how critical telephone service is, even at 3am
in a small town.
*In 1954 the town went dial. The young woman was transferred to a
nearby city to work a dial toll & assistance board. The city board
was a totally different experience than the small town board, the city
board was very structured while the small town was informal (like
"Sarah" in Mayberry). The operator did keep track of where the doctor
and policeman were in case of emergency. The small town board did NOT
handle long distance, all toll calls were forwarded to the next town
where a toll operator handled it.