How does a student relate TIMS “modules” to block diagrams? Why are there red and yellow connectors on both sides of each module and why don’t gain and adjustment control knobs have calibration or level scale markings?

All TIMS modules follow a very strict and consistent "front panel convention". Once a user has been introduced to the TIMS conventions, they will find it very easy to use any TIMS module. The TIMS "front panel conventions" ensure that TIMS modules relate very closely to the Block Diagram representations that are commonly used in telecommunications and signal processing.