DigiTech Midi Implementation Manual page 117

41 Mix:Tap2 L Level 0-10
42 Mix:Tap3 R Level 0-10
43 Mix:Tap3 L Level 0-10
44 Mix:Tap4 R Level 0-10
45 Mix:Tap4 L Level 0-10
11 Algorithm definitions
Each of the 11 algorithm definitions holds a 45 byte program definition (11
* 45 = 495 bytes). The 1st entry is the latest parameter settings for
algorithm 0, the 2nd entry is the latest parameter settings for algorithm 1,
etc. See Program Definitions for the structure of each of the 11 algorithms.
The GSP21 uses this table while changing a program's algorithm.
Program number (GSP21 0-127, GSP21 PRO 0-191)
Program number + 1 is the program that is running in the GSP21.
Midi receive channel (0 - 17)
0 Receive MIDI Disabled
1-16 Receive MIDI on Channel 1-16
17 Receive MIDI on All Channels
Midi transmit channel (0 - 16)
0 Transmit MIDI Disabled
1-16 Transmit MIDI on Channel 1-16