The DIN interface is a five- pin socket used in personalcomputers( PC), formerly used to connect the keyboard, but in the meantime replaced by the smaller PS/2 socket.
The signals routed through the connectors are identical, except for pin 3 of the DIN connector, which is usually unassigned, but can be used to reset the microcontroller.
The DIN connector was also previously used in AV for connecting broadcast and phono equipment such as tape recorders and turntables. They were also known as Tuchel plugs. These were 3- or 5-pin connectors that were commonly used on early microphones, especially in Europe.