Furuno FCV-1200L Service Manual page 10

SIG IN AC Input signal (AC) from external transceiver unit
SIG IN DC Input signal (DC) from external transceiver unit
KP IN H/L Trigger signal inputted from external transceiver unit
KP OUT H/L Trigger signal output for external transceiver unit
TVG/GAIN TVG and GAIN control voltage for external transceiver unit
TD/RD Communication I/O signals to/from NAVAID
TRX TD Transmission data of CPU on MAIN board
CONTD Transmission data of CPU on PNL board
R/G/B Display signal (Red, Green, Blue)
7