In order for Crestron or AMX systems to send a variably-encoded serial string (like a Unison Serial Access Protocol string), special characters are required before each hex value in the string. If you do not add the special characters, the control systems assume the string is ASCII and send it incorrectly. ASCII values do not need any added information.
Example: Trying to send a command to activate Preset 1 in Room 1
USAP Command (generated by USAP Test Utility):
ee17000040Room 1.Preset 1.ACTI0000Crestron (Crestron needs to see a \x before each individual hex value in order to send it.)
ee17000040Room 1.Preset 1.ACTI0000AMX (AMX/Panja adds a $ before each Hex Value.)
$ee$17$00$00$40Room 1.Preset 1.ACTI$00$00