AMX192 has mostly been replaced in favour of DMX, and is typically only found in legacy hardware.
The name AMX192 is derived from analog multiplexing and the maximum number of controllable lighting channels (192).
In the late 1970s, the AMX192 serial analogue multiplexing standard was developed in the US, permitting one cable to control several dimmers.
At about the same time, D54 was developed in the United Kingdom, and differed from AMX192 in that it used an embedded clocking scheme.
AMX192 used a separate differential clock with a driver circuit similar to RS-485, but current limited on each leg with 100Ω resistors.