just a short simple explanation of what they do...
CDS: - Common Display System – An electronic display that shows primary flight, navigation, and engine information.
DEU: - DEU’s are mounted on the aft rack of the EE Compartment; DEU’s collect data from the airplane systems then change the data to a video signal that is sent to the Display units in the cockpit and send the data to other airplane systems.
EEC: - Electronic Engine Control – (Normal mode)
- Controls the HMU electronically (throttle by wire)
- Uses N1 speed to control engine thrust
- Detects hot starts, EGT overshoots, and wet starts
- Provides auto relight
from the only "NG" book I have
"737 Cockpit Companion" by Bill Bulfer