Wiring typically uses 3 cores of a 4 core SWA two twisted pair cable
connected to the terminals on J12 named TXDP, DTRB and GNC inside the
C4000 box. If connecting multiple dispensers, always wire them in parallel.
At the site controller, the terminals may be named: RS485A = TXDP and
RS485B = DTRB. GND = Ground or Earth.
The C4000 box contains mains voltage power. Always isolate
before removing the lid.