The profit: extracting more bandwidth from ready-made tonns of hadware (consoles, dongles, cable, fixtures).
Over the world, circuitry uses MAX 485-like ICs.
- The slope-limited 485 ICs are bound to DMX's 250 kbaud, thus allowing to forget many headaches using ugly cheap almost-broken cables.
- Faster 485 ICs are able to drive 2/6/10 Mbaud. Sure, this time cables can't be almost-broken, but ugly cheap ones still can do good.
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Quater megabaud: Old good DMX-512/RDM using old good splitter and wires. Damn slow, no parity checks, but still able to drive a kilometer of cable.
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Megabaud: bigger frames, more universes - this aspect better to be flexible, but it's 4 times faster. Definetely. WS2812 Led Pixels finely fit this baudrate too.
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Quad/Octa megabaud - even more universes, full-duplex RS-422 topology (not half-duplex RS-485), sure parity checks, frame checksums, closed-loop topology, etc. As a penalty - it can't be an ugly and cheap kilometer cable. As a life-hack, 1/3 kilometer roll of FTP Cat5/6 cable fits (A) couple os RS-422 lanes (B) quad RS-485 lanes (C) Whatever else, analog or digital, that fits 100-700 MHz range.
250kHz uses starcode 0x00, as before
DMX-512 at multiple speed mode uses startcode 0x00 once per 250kHz-timed frame, the rest frames use SC not equal to 0x00
5-pin cable goes true 5-wired as default, allowing to replace RS-485 half-duplex with RS-422 full-duplex. Having full-duplex line, system is capable for closed-loop topology, giving tight mechanic control over DMX hardware you already have (you still need new 5-pin RS-422 DMX splitter)
You know, this story is about kilometer-long cables again.
Checking framing integrity is nice add-on for that story.