Inventions and Inventors Volume 1 - Online Public Access Catalog

Almon B. Strowger
Telephone switching / 753
Some people thought Almon B. Strowger was strange, perhaps
even demented. Certainly, he was hot-tempered, restless,
and argumentative. One thing he was not, however, was unimaginative.
Born near Rochester, New York, in 1839, Strowger was old
enough to fight for the Union at the second battle of Manassas
during the American Civil War. The bloody battle apparently
shattered and embittered him. He wandered slowly west after
the war, taught himself undertaking, and opened a funeral
home in Topeka, Kansas, in 1882. There began his running war
with telephone operators, which continued when he moved his
business to Kansas City.
With the help of technicians (whom he later cheated) he built
the first “collar box,” an automatic switching device, in 1887.
The round contraption held a pencil that could be revolved to
different pins arrange around it in order to change phone connections.
Two years later he produced a more sophisticated device
that was operated by push-button, and despite initial misgivings
brought out a rotary dial device in 1896. That same year
he sold the rights to his patents to business partners for $1,800
and his share in Strowger Automatic Dial Telephone Exchange
for $10,000 in 1898. He moved to St. Petersburg, Florida, and
opened a small hotel, dying there in 1902. It surely would have
done his temper no good to learn that fourteen years later the
Bell system bought his patents for $2.5 million.
of digital switching was not pursued. New versions of the ESS continued
to employ electromechanical technology, although mechanical
switching elements can cause impulse noise in voice signals and
are larger and more difficult to maintain than electronic switching
elements. Ten years later, however, Bell Labs began to develop a digital
toll switch, the ESS-4, in which both switching and control functions
were electronic.
Although the ESS-1 was the first electronically controlled switching
system, it did not switch voices electronically. The ESS-1 used
computer control to move mechanical contacts in order to establish
a conversation. In a fully electronic switching system, the voices are