Let's start with the RCA connector also known as phono because it was designed to connect a turntable to a radio receiver used as an amplifier; also called cinch from the name of the Cinch Connectors industry that produced it.
RCA connector
The name RCA instead it comes from the US electronics company of the same name that designed it over the years '40 of the '900. This pin is provided with two internal contacts, one carrying the signal which ends in the tip and the other which is on the ring constitutes the ground. It carries only one unbalanced electrical signal (mono audio), but can also be used for video signals (the yellow connector shown in the photo) with coaxial cables that have impedance 75 Ohm. It is typically used in the audio field in consumer electronics since it has been around for years '50 of the '900 has gradually supplanted the jack connector e DIN becoming a connection standard Hifi.
Jack connectors
Invented in 1878 for use in telephone exchanges, the Jacks it is currently the oldest standard of electrical connector still in use today. Can dispose from 2 a 5 contacts and, depending on how many there are, it finds different uses and names, that is: Jack TS 2 contacts for connecting an unbalanced mono audio signal; Jack TRS 3 contacts to connect a stereo or balanced mono signal; Jack TRRS 4 contacts to connect a stereo signal plus microphone or video channel; Jack TRRRS 5 contacts to connect in some portable devices with dual microphone or stereo balanced output. Finally, the various types of Jacks also differ in the diameter of the connector and are: Submini jack having a diameter of 2,5 mm o 3 / 32 " usually used in smartphones, tablets and computers; Mini-jack having a diameter of 3,5 mm o 1 / 8 " mainly used in consumer headphones; Jack having a diameter of 6,35 mm o 1/4"Mainly used in professional headphones, electric musical instruments, amplifiers, etc…; NATO plug having a diameter of 7,13 mm o 0,280" used exclusively in aviation headsets.
XLR connector
Also known as Cannon in reference to the US manufacturer who built it for the first time in 1950: the Cannon Electric which is now part of the group IT Corporation, XLR connector whose abbreviation refers to the original name which was Cannon X to which a safety lock was added (Latch) and a rubber insulator (Rubber) around the poles. This plug is used to make balanced connections allowing you to connect devices over a long distance without loss of quality due to the background noise picked up. This is made possible by the presence of: mass (1), a cable of signal (2) and a signal out of phase 180 ° (3). At the opposite end of the connection, on both these cables, in addition to the actual signal, the same amount of background noise possibly picked up along the path is in phase; the signal will then be taken from the two cables by difference in this way the useful part will be doubled in amplitude, while the noise intercepted along the path, being present in phase on both cables, will be canceled. XLRs exist in different versions: 3 poles typically used to connect microphones and balanced lines; 4 poles used for connecting headphones or for carrying low voltage direct current power supply; 5 poles used for communications systems, microphone headsets, computer control of stage lights; 6 pole used for dual channel communication locations, where each channel uses three of the six available poles.
DIN connectors
Acronym for German institute for standardization (long-standing national standardization institute of Germany) il DIN it is an electrical connector which, as shown in the figure below, can have from 3 a 8 pin. Given its low manufacturing cost, it had a very large production and was used in various fields from audio to information technology; version a 6 pin for example, subsequently called the PS2 connector, it was used to connect the keyboard to the computer, becoming a standard for decades. The 3-pin version has been widely used to connect professional microphones instead of the XLR connector, becoming the connection standard since the early years '70 of the '900. DIN4 found use as a connector S-Video. The five pin instead found use in the MIDI, Short for Musical Intool Digital Interface, that is the standard protocol for the interaction of electronic musical instruments, also through a computer; born over the years '80 of the '900 it has remained virtually unchanged and is currently still used in electronic music. Finally the DIN connectors a 7 e 8 poles they were used for computer connections such as the Commodore 64 and game consoles like the Sega Mega Drive. In the middle of the years '90 of the '900, new technologies have taken over such as the cable in optical fiber and digital video that forced the DIN connector to pass from the world standard to an electronic product confined to a few areas.
