Hello,
How do you send a Controller Change, or a Program Change? A Note On message would be very similar to those, and NOT to a SysEx message, which is something quite separate.
It is not impossible that a specific device might have a way to incorporate a Note On message inside a SysEx message, bu it would be something totally specific to that device, and very strange given that a Note On message is standard to almost every midi device regardless of SysEx.
A note on message would comprise 3 bytes, being &H9c where c is the channel in the range 0 to F, &Hnn where nn is the note number, and &Hvv where vv is the velocity (volume) (range 1 to 7F, 0 would in fact signify Note Off). Data like this in a midi file would be preceeded with a delta time value, which may not be required here, if the three bytes do not do anything try using a preceeding byte of 0 (zero) to act as a timing byte for immediate action. But, as this is divorced from the header of a midi file, the system will have no idea what the timing is anyway??
Of course, any device that does do something via SysEx coule use a totally different message detail!
Geoff