MAGAZINE SOBRE HISTÒRIA (Iniciat com AUCA satírica el 1960.. en edició de M. Capdevila a la classe de F.E.N. )
"La història l'escriu qui guanya".. així.. "El poble que no coneix la seva història... es veurà obligat a repetir-la.."
|01-03-2016 (701 lectures)||Categoria: Articles|
Modern phone connectors are available in three standard sizes. The original¬†1‚ĀĄ4 in (6.35¬†mm) version dates from 1878, when it was used for¬†manual telephone exchanges, making it possibly the oldest electrical connector standard still in use.
The 3.5¬†mm or¬†miniature and 2.5¬†mm or¬†sub-miniature sizes were originally designed as two-conductor connectors for earpieces on¬†transistor radios. The 3.5¬†mm connector, which is the most commonly used in portable application today, has been around at least since the Sony EFM-117J radio which was released in 1964. It became very popular with its application on the¬†Walkman in 1979.
The 3.5¬†mm and 2.5¬†mm sizes are also referred to as¬†1‚ĀĄ8 in and¬†3‚ĀĄ32 in respectively in the United States, though those dimensions are only approximations. All three sizes are now readily available in two-conductor (unbalanced mono) and three-conductor (balanced mono or unbalanced¬†stereo) versions.
Four- and five-conductor versions of the 3.5¬†mm plug are used for certain applications. A four-conductor version is often used in compact¬†camcorders and portable media players, and sometimes also in¬†laptop computers and¬†smartphones, providing stereo sound plus a video signal. Proprietary interfaces using both four- and five-conductor versions exist, where the extra conductors are used to supply power for accessories. The four-conductor 3.5¬†mm plug is also used as a speaker-microphone connector on handheld¬†amateur radio transceivers from¬†Yaesu and on some¬†mobile phones.
The most common arrangement remains to have the male plug on the cable and the female socket mounted in a piece of equipment: the original intention of the design. A considerable variety of line plugs and panel sockets is available, including plugs suiting various cable sizes, right-angle plugs, and both plugs and sockets in a variety of price ranges and with current capacities up to 15¬†amperes for certain heavy duty¬†1‚ĀĄ4 in versions intended forloudspeaker connections.