Could be a few things. Depending on how the RTI system likes to see strings expressed. The Crestron module spits out the following string to raise the volume of output one a single increment step:
\x91\x03\x01\x01\x41
Baud rate 115200 8, 1, none
Bruce Sinclair CMB Integrations LLC DMC-E "Those who are most critical, often have no real skills themsevles"