The K-type socket is present on some home recorders and is standard on most portables. It is commonly used to connect a camera, but other devices can utilize it. Such as an camera adapter, titler, or color corrector. It provides access to video and audio in and out, pause, record review, tally (device matching), and 12 volts DC out. It depends on the accessory, model, and the application for which it is used. The socket shown is on the left side of the SL-2000 portable VCR.