Furuno BB FAR28x7 - Manual (Page 275)

APPENDIX
AP-27
Serial interface – input ports
Heading sensor
Transmission rate is selectable from 4800 bps and 38.4 kbps.
LTC1535
RD-A
GND
Isolated RS485 Transceiver
Logical High: A-B> +0.2V
Logical Low: A-B< -0.2V
RD-B
Log/navigator
PC-400
RD-A
RD-B
Photo Coupler
470 ohm
This port is an opticoupler used to isolate I/F terminal on RD terminal.
Absolute maximum rating
Input
Forward current: 50 mA
Reverse voltage: 6 V
Output
Supply voltage: 16 V
High level output voltage: 16 V
Low level output current: 50 mA