Talker Identifiers NMEA 0183

AG       Autopilot - General
AP       Autopilot - Magnetic
CD       Communications – Digital Selective Calling (DSC)
CR       Communications – Receiver / Beacon Receiver
CS       Communications – Satellite
CT        Communications – Radio-Telephone (MF/HF)
CV       Communications – Radio-Telephone (VHF)
CX       Communications – Scanning Receiver
DF        Direction Finder
EC        Electronic Chart Display & Information System (ECDIS)
EP        Emergency Position Indicating Beacon (EPIRB)
ER        Engine Room Monitoring Systems
GP        Global Positioning System (GPS)
HC        Heading – Magnetic Compass
HE        Heading – North Seeking Gyro
HN        Heading – Non North Seeking Gyro
II          Integrated Instrumentation
IN         Integrated Navigation
LC         Loran C
P           Proprietary Code
RA         RADAR and/or ARPA
SD         Sounder, Depth
SN         Electronic Positioning System, other/general
SS         Sounder, Scanning
TI          Turn Rate Indicator
VD         Velocity Sensor, Doppler, other/general
DM         Velocity Sensor, Speed Log, Water, Magnetic
VW        Velocity Sensor, Speed Log, Water, Mechanical
WI         Weather Instruments
YX         Transducer
ZA         Timekeeper – Atomic Clock
ZC         Timekeeper – Chronometer
ZQ         Timekeeper – Quartz
ZV         Timekeeper – Radio Update, WWV or WWVH