Furuno GP-80 - Manual (Page 14)

5. INITIAL SETTINGS
11
Input data sentence of NMEA 0183 Ver. 1.5/2.0
Checksum is checked if attached, and if any errors are found, the sentence becomes invalid.
Talker ID is not distinguished.
DBT: Depth below transducer
$--DBT, 1234.5, f, 1234.5, M, 1234.5, F*12
a b c d e f g
a, b: Water depth, feet
c, d: Water depth, m
e, f: Water depth, fathoms
g: checksum
DPT: Depth
$--DPT, 1234.5, 1234.5*23
a b c
a:
Water depth relative to the transducer, meters
b: Offset from transducer, meters...not used
c: checksum
MTW: Water temperature
$--MTW, 23.4, C*34
a b c
a, b: Temperature, degrees C
c: checksum
TLL: Target latitude and longitude
$--TLL, 00, 3445.678, N, 13521.234, E, abcd, 121530, T, R*A5
a b c d e f g h i j
a: Target number...not used
b, c: Latitude
d, e: Longitude
f:
Target name...not used
g: UTC...not used
h: Target status...not used
i:
Reference target...not used
j: checksum
FURUNO proprietary sentences