Miditech MIDI THRU 4/ FILTER Owner's Manual page 25

How to select filter MIDI system message type:
1.Hold down and press the PANIC button minimum 5 Seconds
while plugging the MIDI In to power the system. The LED
flashes, to show that you are now in "setup mode" .
2. Set switch 7 to ON
3. Press keyboard, a white key is to filter System Exclusive
Messages. a black key is to filter Common Messages, if you
press both white and black keys, filter both.
If you specify to filter the Sys Ex events, e.g. the table is 41H,
00H, 42H, 12H, 40H, (all Roland GS SysEx start from these
bytes). If MIDI IN a GS Reset SysEx: F0H, 41H, 00H, 42H,
12H, 40H, 00H, 7FH, 00H, 00H, F7H, it match the filter table,
should not send MIDI OUT.
But another SysEx, F0H, 01H, 02H, 03H, F7H, should not
been filtered and send MIDI OUT.
If you choose to filter both, the MIDI THRU 4 / Filter filters
any MIDI System and Common event. (F0H, F1H, F2H, F3H,
F6H)
4. To confirm the changed setup, press the Panic button a short
time again. After this the box starts again with the work mode.
How to select filter MIDI Realtime message type:
If switch 8 is at ON position, it filters any MIDI Real event.
(F8H, FAH, FBH, FCH, FEH, FFH)
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