John,

I have searched this forum and found a lot of information on how to get these two units to work together, but after much troubleshooting I still am at a loss. The GCX I have is an older Digital Music Corp. labeled unit just FYI.

I understand that you have to "trick" the GCX when controlling it from the All Access by sending it a sysex string of F0 00 00 07 01 08 10 F7. I have the Rocktron sending this sysex string and the "Active" LED on the GCX turns on and stays lit. The problem is that the GCX is still not responding the the MIDI CC messages (Control Change 80-87 on MIDI channel 16) that I am sending it from the Rocktron to switch the 8 loops on/off. The Rocktron is sending the correct MIDI CC messages to the GCX and the "Active" LED on the GCX flashes when it receives the message, but the none of the loops switch on/off.

I have an older first version Ground Control pedal that I have been using with the GCX up to this point. The strange thing is that if I start up the GCX with the Ground Control then plug in the Rocktron, the GCX responds to the MIDI CC messages from the Rocktron and swithes all 8 loops on/off.

I've used a MIDI monitor program to monitor the output of the Rocktron and the original Ground Control to make sure the sysex string is the same and it appears to be the same message "Digital Music Corp 8byte". All the MIDI CC messages match up as well between the two units when monitoring the output messages.

If you have any other ideas it would be greatly appreciated. Hopefully I am just missing something??

Thanks!!

Well, looks like I got it figured out, and I will respond to my own question in hopes that it will help someone else out in the future.

The problem was with the ALL ACCESS sysex string, see below:

First pick a preset you are not going to use but for this purpose.
Name it " Ground Hog " because it needs to re-live the same thing again everyday !

F0 00 00 07 01 08 10 F7 remember this string is hexadecimal.
I have found that all numbers the All Access uses are Decimal please keep this in mind.
So if the controller number you need is 80 the All Access wants 80

So keep these two decimal numbers in mind .
00= 0
7F= 127
Okay back to the SYSEX corral!

PRESS 2ND
PRESS SWITCH 5 [ SYSX ]
PRESS SWITCH 9 [ -> ]
PRESS SWITCH 7 [INC] to ON = F0 H
PRESS SWITCH 9 [ -> ] BYTE 1
PRESS SWITCH 7 to show 0 = 00H
PRESS SWITCH 6 [ INC] BYTE 2
PRESS SWITCH 7 [ INC] to show 0 = 00H
PRESS SWITCH 6 [ INC] BYTE 3
PRESS SWITCH 7 [ INC] to show 7 = 07H
PRESS SWITCH 6 [ INC] BYTE 4
PRESS SWITCH 7 [ INC] to show 1 = 01H
PRESS SWITCH 6 [ INC] BYTE 5
PRESS SWITCH 7 [ INC] to show 8 = 08H
PRESS SWITCH 6 [ INC] BYTE 6
PRESS SWITCH 7 [ INC] to show 16 = 10H [Note the All Access is looking for the decimal equivalent instead of pure hex ]
PRESS SWITCH 6 [ INC] BYTE 7
PRESS SWITCH 7 [ INC] to show EOX = F7H

Which equals F0 00 00 07 01 08 10 F7

EXIT 2ND

It is advised to re-enter 2ND and check your message to verify the All ACCESS has stored the information correctly

PRESS 2ND
PRESS switch 5 [ SYSX ]
PRESS SWITCH 9 [ -> ]
VERIFY SYSX is set to ON = F0H
PRESS SWITCH 9 [ -> ]
VERIFY BYTE 1> 0 = 00H
USING SWITCH 6 [INC] VERIFY THE FOLLOWING
BYTE 2 >0 = 00H
BYTE 3 >7 = 07H
BYTE 4 >1 = 01H
BYTE 5 >8 = 08H
BYTE 6 >16 = 10H
BYTE 7>EOX = F7H

PRESS 2nd AND YOUR DONE !

Glad you found it, but I feel I have to point out that you never needed to send the SysEx message to get the GCX to start working... you could have just started sending the Control Change messages. No harm in sending it, but with only a single GCX in the rig, it isn't necessary.

It is the Pedal Switcher that requires the above mentioned SysEx message so it will act as if it were the first four GCX loops.

Good Luck!