Furuno FAR21x7 & BB FAR28x7 Operator's Manual BB FAR28x7 - Page 276

APPENDIX
AP-28
Serial interface – output ports
ARPA for ECDIS
SN751178NS
RD-A
RD-B
Dual differrential
drivers and receivers
Logical High: A-B> +0.2V
Logical Low: A-B< -0.2V
Serial interface – input/output ports
Transmission rate is selectable from 4800 bps and 38.4 kbps.
Input port (RD-A, B)
LTC1535
RD-A
GND
Isolated RS485 Transceiver
Logical High: A-B> +0.2V
Logical Low: A-B< -0.2V
RD-B
Output port (TD-A, B)
LTC1535
TD-A
GND
Isolated RS485 Transceiver
Logical High: A-B> +4.0V
Logical Low: A-B> -4.0V
TD-B