It could be the connection between your system and the projector was not appropriately built. Please make sure the following items are functional -
1. The baud rate in projector OSD menu should be identical with the setting on Extron Dataviewer or Tera term. For example, to set baud rate as 115200 on the projector and baud rate on Extron Dataviewer or Tera term as 115200 too. 2. Make sure the RS-232 cable is "Crossover" type.
3. If using RS-232 with USB, make sure the USB driver is correctly installed. Also, the Com port should be correctly selected.
4. If connection was built, when press "Enter", you will see the projector echos a ">" in Extron Dataviewer or Tera Term window.