Yamaha SPX1000 Operation Manual page 59

3.Receiving Conditions
4 . Reception Data
4-1. Channel information
1 ) Channel voice messages
Note On
Reception is enabled on the MIDI channel of the currently selected bank. For
programs of Memory Nos. 1 - 5 , 1 9 , and 2 6 , if the parameter of MIDI TRG. is ON,
this is received as a trigger.
For programs of Memory Nos. 20 - 24, 3 9 , and 40, this is received as a message
to control pitch variation. The velocity value is ignored. Reception is not
possible when the Base Key parameter is OFF.
Add-22
MIDI T R G . ( B A S E KEY)