Help!! Has anyone ever controlled a Shure DFR11EQ via RS 232

gregbentley

Has anyone ever successfully controlled a Shure DFR11EQ? I have a project with some of these boxes, I looked at the Shure RS 232 command set, not the most user friendly command set. I need to ramp volume and mute only. Has anyone ever done this, or can interpret this command set? All help is appreciated. Thanks.

VLCNCRZR

Just reading this document gives me a headache!

This is where I would burn the document and integrate an AMX
volume card somewhere pre or post.

Frankie

I agree AMX Vol3 or Vol4.

gregbentley

DFREQ11 Replies

Unfortunately an AMX vol box is not an option, believe me if it was I would have already gone there. Anyone else know about this protocol?

NMarkRoberts

That has to be the worst protocol I have ever seen, even though it is written in proper English - but it looks achievable. The only problem will be the amount of time you wil have to spend experimenting until it works!

Cabling

Ooh err, that sounds worrying.

Device ID

I would guess that this should be $00.

ww,xx,yy

This appears to be some sort of timing thing. Disable the delay in bit 1 of "Bypass" and I think you can just set all of these to $00.

WW,XX,YY

WW0 = TRUNCATE[G/10000h]
XX0 = TRUNCATE[(G - WW0)/100h]
YY0 = G- WW0 - XX0

It appears that these three bytes hold the gain setting where WW is the high order byte, XX and YY low order.

However the code sample looks wrong; I think it should be:

WW0 = TRUNCATE[G/10000h]
XX0 = TRUNCATE[(G - (WW0 * 10000h))/100h]
YY0 = G- (WW0 * 10000h) - (XX0 * 100h)

Although I would welcome enlightenment!

Disregard XX and YY (set them to $00) because who cares about infinitesimally small changes in gain. Let's assume you want a gain range of $00..$FF. So:

WW = nGain BAND $7F

What happens to the top bit? See below.

SS

This appears to contain all of the high order bits of ww,xx,yy,WW,XX,YY. Incredible, I know, but the top bit of every byte except the start and stop bytes is zero, so there is method to this madness.

WW appears to be in the 4th highest or 4th lowest bit - I get dizzy trying to work out which. So experiment with setting SS to $8 or $10 when nGain BAND $80 is on.

Bypass

Reasonably obvious.

Checksum

Most bytes are $00 so this just needs

Checksum = $7F bxor SS bxor WW

The checksum will fail if you get SS wrong so start with a low gain level so that SS is always $00.

Best of luck, and you'll need it!