I'm trying to control viewsonic LDM136-151 display via rs-232 from crestron CP4N but have had no luck. The commands are correct and verified. What am I missing?Is there any setting on display that need to be turned on? I have controlled numerous viewsonic display with the viewsonic rs-232 driver baked in the database.

After glancing at the manual there doesn't seem to be any config needed to the settings, but there is one blip where they mention "NOTE: Make sure the Control Board Switch is switched to the left for RS-232
control." on page 186. Otherwise good luck man