Carrier 50EJQ Installation, Start-Up And Service Instructions Manual page 10

Fig. 10 — Control Board Diagram
LEGEND
CCN — Carrier Comfort Network N.O. — Normally Open
COM — Common R
D — Diode SIO
DIP — Dual In-Line Package SW
LED — Light-Emitting Diode T
N.C. — Normally Closed
— Relay
— Serial Input/Output
— Switch
— Terminal