From memory, I believe these add-on modules came into their own when using the 454A with the (gold old) medTester 5000-C.
Specifically, the REM/ARM module or the combined REM/ARM and Return Fault module (RARF) were used during the medTester CQM (Contact Quality Monitor) Test.
The CQM test measured the resistance needed by the ESU to activate the CQM alarm.
The RARF was also needed for the medTester Return Fault Test.
But, as mentioned in Chapter 5 of the manual you refer to, those two modules were specifically aimed at a particular type of ESU (eg:- Valleylab Force 4B) so may, or may not, be of use when testing other ESU's.
The (nine) "Ohm Test Load" modules may be used in cases where ESU tests call for specific loads.
Do you have the modules? The one you show looks like a RARF.
