是灯光控制协议

The U.S. Institute of Theater Technology (USITT) originally created the DMX512 protocol in 1986 【20】. A revision was made four years after, but since then the protocol has not changed. This is both good and bad for those using the protocol. It is good because it maintains compatibility between most devices able to communicate using this protocol. Unfortunately, it is also a bad thing because DMX512 is not considered an official standard and thus each manufacturer is able to make their own subtle changes as they see fit. For example, the specification calls for a 5-pin XLR connector connecting 5 wires for a total of two data links and one common. The second data link is optional, so some manufacturers use 3-pin XLR connectors to allow the use of standard microphone cables. Although this sounds like a good idea (two uses for one product), most microphone cables are not made properly to comply with the DMX512 specification and have been known to cause communication problems between devices 【19】.