Hi I might be able to help what exactly do you want know about sysex its alargish subject and as the name sugest exclusive to peice equipment you are using. System exclusve genrally lets you send or receive certain memory areas that contain data about how the synth is programed. Do send or recieve to these areas you need to know what it you want send or recieve there are set of genral protocols that identify the unit number and the manufacturer. Roland synths also utilisae something called a checksum which helps check that data that was received was error free. You would have to check with roland how to do this and you use the maths section of excel to help you calculate it(saves time over using a calculator. Any way sorry if i couldn't be more specific at this point.
regards
Rick