So all modules daisy-chained with a load in a dummy plug at the end unit. Another way, but more open to installer abuse is 3 connections in the plug and a load in every unit connected across one of the 485 legs and the third pin. A shorting link between the third pin and the other leg completes the circuit on the end unit only.
Thanx, both require installation by someone that can read, my customers claim the can not afford to hire such people.

Erik