Title :
Subsequent developments in telephone instruments
Author :
Richards, D.L. ; Connolly, D.C.A.
Author_Institution :
General Post Office, Research Department, Telephony, Transmission Performance Section, London, UK
fDate :
3/1/1976 12:00:00 AM
Abstract :
One of the most fruitful inventions in telephony took place at Bolton Percy, Yorkshire. A country curate discovered that crushed coke made a very good material for a variable-resistance microphone. That was in 1878. By 1957, the microphone and earphone that are used in almost all British Post Office telephone sets today were developed
Journal_Title :
Electronics and Power
DOI :
10.1049/ep.1976.0079
