One things to note, that if the camera is connected to the codec using the it's control cable, than the IR on the codec will be disabled.  The camera's IR takes precedence over the codec's.

SystemUnit IrSensor Mode
Both the Codec C Series and PrecisionHD camera have IR sensors, and only one of them needs to be 
enabled at the time. The IR sensor LED is located on the front of the codec and the camera and flickers 
when an IR signal is received from the remote control.
Requires user role: ADMIN
Value space: 
On: Enable the IR sensor on the codec.
Off: Disable the IR sensor on the codec.
Auto: The system will automatically disable the IR sensor on the codec if the IR sensor at camera is enabled. Otherwise, the IR sensor on the codec will be enabled.