WattMaster WCC II - Manual (Page 214)

Section 5: Installation Guide
WCC II Operator’s Guide
Operator Interfaces 5-12
The communication loop wire from the CPU is connected to one
of the “R/T” and one of the “C” terminals on the satellite controller
which is physically located nearest the CPU. The other “ R/T”
and “ C” terminals located on the satellite controller can be used
to extend the two-wire loop to the next satellite controller, or the
wires can branch off of a two-wire loop running through the center
of a building as shown below: