Aux 4 press \x10\x02\x01\x13\x00&\x10\x03
Aux 4 release \x10\x02\x02\x13\x00'\x10\x03
Aux 5 press \x10\x02\x01\x14\x00'\x10\x03
Aux 5 release \x10\x02\x02\x13\x00(\x10\x03
Aux 6 press \x10\x02\x01\x15\x00(\x10\x03
Aux 6 release \x10\x02\x02\x13\x00)\x10\x03
These commands were taken directly off the output of a Crestron processor so the checksums and whatnot should be correct
baud 19200
data bits 8
stop bits 2
parirty none
straight thru DB-9 M to F cable all nine pins connected
good luck!