Microphone connector
Many different electrical connectors have been used to connect microphones to audio equipment—including PA systems, radios, tape recorders, and numerous other devices. Phone connectors Photo: 2.5 mm mono (TS), 3.5 mm mono and stereo (TRS), and stereo (TRS) phone connectors The most common microphone connector in consumer use is the venerable phone connector, in , 3.5 mm, and 2.5 mm sizes, and in both mono and stereo configurations. Not all microphone plugs with 3-segment TRS (Tip-Ring-Sleeve) connectors are actually stereo. Most computer microphones use the third segment to carry bias power for the microphone. Type "O" 1930s connectors These round connectors are about 1 inch in diameter. They were in common use in the later 40's and thru the 50's at WELI, New Haven Connecticut. see: http://terryking.us/OldRadio/OP-4-RCA-RemoteAmplifier-1934-Rear.jpg The 3 connectors on the left are 1934 type "P" round microphone connectors. They look like this: http://terryking.us/OldRadio/P-CG-12S.jpg Type "UA" 1950s–1960s professional connectors These were "D" shaped upgrades of the old P connectors, with gold plated pins and sockets. They looked like this: http://terryking.us/OldRadio/UA-3-12.jpg SwitchCraft 2501F/2501M This is the part number for a Swichcraft connector used with high impedance microphones up through about 1980. It was intended for coax style cable up to