Termination Switches on Console I/O Cards (DMX ports on consoles and Gadget I/II)

The three possible positions on a console I/O card have the following functionality:

DMX or OUT or SOURCE– The device is the DMX source, this is the default and generally what it should be left on
OFF – No termination. Used for Thru applications where the device may not be at an end of the line (very uncommon)
RDM or IN or END– The device is at the end of the line and not a controller/transmitter. (Reserved for future implementation)