Furuno RD-50 Operator's Manual page 81

RMC - Recommended minimum specific GPS data
$ RMC, hhmmss.ss, A, llll.lll, a, yyyyy.yyy, a, x.x, x.x, xxxxxx, x.x, a, a*hh<CR><LF>
--
Note: A=Autonomous, D=Differential, E=Estimated (dead reckoning), M=Manual input,
S=Simulator, N=Data not valid
ROT - Rate of turn
$ ROT, x.x, A*hh<CR><LF>
--
Status: A=data valid, V=data invalid
Rate of turn, deg/min, "-"=bow turns to port
RPM - Revolutions
$--RPM, a, x, x.x, x.x, A*hh<CR><LF>
Propeller pitch, % of maximum, "-"=astern
Speed, revolutions/min, "-"=counter-clockwise
Engine or shaft number, numbered from centre-line
odd=starboard, even=port, 0=single or on centre-line
Source, shaft/engine S/E
RSA - Rudder sensor angle
$--RSA, x.x, A, x.x, A*hh<CR><LF>
Starboard (or single) rudder sensor (see Note 1 and 2)
Status, A=data valid, V=data invalid
Note 1: Relative measurement of rudder angle without units, "-"=bow turn
to port. Sensor output is proportional to rudder angle but not necessarily 1:1.
Note 2: The status field should not be a null field.
Latitude, N/S
Status: A=data valid, V=navigation receiver warning
UTC of position fix
Checksum
Checksum
Status: A=data valid, V=data invalid
Port rudder sensor (see Note 1 and 2)
Status, A=data valid, V=data invalid
APPENDIX 4 DIGITAL INTERFACE
Date: dd/mm/yy
Course over ground, degrees true
Speed over ground, knots
Longitude, E/W
Checksum
Mode indicator
(see Note)
Magnetic variation,
degrees, E/W
AP-11