The Dell 2400MP video projector has an RS232 connector on the back that makes it possible to control the projector via simple byte sequence commands. This document describes what you need to get this to work fairly simply. The Dell documentation is pretty sparse.
The example scripts are batch files that should work with pretty much any version of Windows or even DOS. I've only tested it using Windows XP. It should be trivial to get this working on Linux.
For authoritative reference see this PDF at the Dell support site describing all the 2400MP RS232 protocol commands.
Fig. 1 - RS232 connector in back of the projector (lower right corner.)
Fig. 2 - Pinout of the 6-pin mini-DIN connector (facing the back of the projector.)
Fig. 3 - The pin connections from the mini-DIN connector to a standard DB9 connector.
And here's a home-made RS232 female DB-9 to male 6-pin mini-DIN adapter:
All you need then is a standard RS232 cable of whatever length you require to connect the adapter to the controlling computer.
These two files are required by the scripts. They contain the byte sequences to perform the actual commands.