EXTERNAL CONTROL SYSTEMS
Over the years data-exchange protocols have been introduced and developed by individual equipment manufacturers to permit different pieces of AV equipment to ‘talk’ to each other. Some, like the SCART pin 10/12 just described, are ad-hoc systems designed for expediency and thus non-standard, while others (primarily the LANC system designed by Sony) are well established and have been adopted by other manufacturers. Primarily used for edit control (see below), some (LANC, JLIP) are applicable to signal networking and software setting of equipment like camcorders, digital or analogue.
The Sony LANC system uses a single serial data link with address, mode, data status and command bytes, broadly similar to the I2C and D2B buses already described, but not directly compatible with them; it connects via a 5-pin plug or a miniature jack plug, and is very versatile. Panasonic’s edit system is not so developed as LANC; its operation is largely confined to Panasonic videorecorders and cam- corders, and ‘freelance’ makes of edit controllers. Again serial data is used, here in 5-pin or 11-pin special connecting plugs and leads.
JVC have a system called JLIP (Joint Level Interface Protocol) which is primarily designed for remote control and edit functions using a PC. It uses a simple serial data format with eight data, one start, one stop and one parity bit, using a 3.5 mm mini-jack plug/ socket having four connections: one unused, one ground, one data send and one data receive.
None of these communication systems is compatible with any other, which generally means that the equipment at each end of the link must be of the same (or allied) make.