OT: anybody recognises this protocol?

[Don Y]

Bert Thomas wrote:
> Captured between video processor (olympus) and video printer:
> 
> -> [2][0][3][FF][FC][1][83][18][3]
> <- [2][0][2][FF][FD][81][8][3]
> -> [2][0][3][FF][FC][1][89][20][3]
> <- [2][0][2][FF][FD][81][8][3]
> 
> (values in hex, just a sample)
> 
> Does anybody recognise this protocol ?

not off-hand...

STX NUL 3 <16bit> <d1> <d2> <d3> ETX
STX NUL 2 <16bit> <d1> <d2> ETX
...

???

Are all of the messages this same format ("3" parameters
TO the device, "2" parameters FROM)?

Presumably, when actual video is sent, the packets get
larger -- but do they fit the same sort of (suggested)
template?

Does the device chatter constantly?  Or, do these message
exchanges arise ONLY when some event triggers them?

> I'll fill in the context if needed, now left off to reduce noise.