Question
How come DMX is so confusing? Is DMX for servo motors the same thing as DMX for RGB LED strips?
Answer
Yes, DMX is indeed confusing. First of all, there are very roughly two kinds of DMX's:
Dynamixel's DMX or LewanSoul's serial bus servos use simplex UART or RS485 to daisy chained servos. Each servo can send and receive signals, so two wires are used for each daisy chain of servos.
DMX WS2812B LED controllers, and only one send wire is need to communicate with all LEDs in each daisy chain. For WS2812B RGB LED strips, one wire is needed for each strip. So say, for three R, G, B strips, four wires: R, G, B, COM are required.
You might like to watch the video in Ref 1 to get a rough idea of the LED DMX controller and how to control the LEDs. For more details of the real DMX controllers, you can skim the 50+ pages of the catalog listed in the reference below.
References
(1) How to Control LED Tape With DMX - Worship Leader Hangout, 2018aug07 144,494 views
(2) LED DMX Controller Catalog (54 pages!) - AliEXpress
(3) K-8000C Manual