I've not had a chance to try this as I'm away from my test setup, but this is what Stage Research had to say about what is happening when they send a MSC command to Catalyst.

I had originally stated the following...

"Showman is exporting this hex string for a GO command on cue 1.5 on Channel 8 - F0 7F 08 02 40 01 31 2E 35 F7. Cue 1.5 is triggered just fine in Catalyst. SFX is exporting this hex string for the same command - F0 7F 08 02 40 01 31 2E 35 00 00 F7. Catalyst does nothing but receives the command and displays "1.5::" in the MSC Last GO window. What are those extra four zeros and how do I get rid of them?"

Their response is...

"Those zeros delimit the cue list and the cue path. According to the MSC
spec, the sending device can optionally omit them (like ShowMan is doing)
but the spec says:

Controlled Devices should be able to accept more than one set of delimiter
bytes, including directly before F7H, and even if no Q_number, Q_list or
Q_path data are sent.

It goes on to say:

Controlled Devices which do not support Q_list (or Q_path) data must detect
the 00H byte immediately after the Q_number (or Q_list) data and then
discard all data until F7H is detected.

That means that it's Catalyst that isn't working properly because it should
be handling those zeros.

The first thing I would try is to put in 1 for the cue list and 1 for the
cue path and see if Catalyst will read that and probably ignore it. I'm
thinking that Catalyst is freaking out because it's finding two delimiters
next to each other (again, which it's supposed to be able to handle)."

Again, I have not been able to try this yet, but do they have a point about Catalyst not handling the MSC command as per the MSC spec? I will give it a go and post results as soon as I have them.

Richard - Show is at Birmingham Rep. Loading in on Monday, tech starting Tuesday afternoon. Will be at PLASA tomorrow, and in London doing another show the following week with DMX triggers (something I am much more familiar and comfortable with).

Thanks for your help,

Kevin