Almon Brown Strowger
Born September 5 1829 – Died March 14 1908
Patent No. 447,918
Almon Strowger, an undertaker from Kansas City, Missouri, invented a
mechanism that revolutionized the telephone industry and controlled
telephone networks worldwide for much of the twentieth century.
Strowger’s device consisted of buttons a caller tapped to signal the
desired number to a central switch, and a rotating arm at the central
switch that moved the caller’s line until it was in contact with the
desired number. Strowger designed each unit to make a large number of
lines available and to be combinable to scale dramatically without
increasing complexity. The first automatic telephone exchange was
installed in La Porte, Indiana in 1892.
The inventor incorporated Strowger Automatic Telephone Exchange in 1891.
With enhancements to his original design, including a rotary dial,
Strowger’s switching devices were standard equipment in telephone
systems worldwide until the advent of touch-tone dialing in the late
Strowger was born in Penfield, New York, one of seven brothers. He
was a schoolteacher and served in the Union cavalry in the Civil War
before taking up the profession of undertaking. Frustration over human
telephone operators misdirecting his customers’ calls is said to have
inspired Strowger to invent the automatic telephone switching system.