Operation Manual

50 Issue 1 M-2 AIS Operation
External EPFS lost (Alarm 25)
This message indicates that the transponder is no longer receiving data from the
vessel's on-board GPS system. This message should be investigated
immediately.
No position sensor in use (Alarm 26)
This message indicates that the M-2 transponder is unable to obtain a location
fix from either the internal GPS module or from the ship's own GNSS system.
This message may occur during the first few minutes of operation while the
transponder waits to obtain its location, and may safely be ignored during this
time. If the message occurs at any other time, it indicates a possible problem
with the GNSS antennae or wiring and should be investigated immediately
No valid SOG information (Alarm 29)
No valid COG information (Alarm 30)
Heading lost/invalid (Alarm 32)
No valid ROT information (Alarm 35)
These messages indicate that information from various sensors - ie the Speed
over Ground, Course over Ground, heading and Rate of Turn respectively - are
not available. In a full installation it is expected that all this information will be
available permanently and the display of one or more of these messages is an
indication that there may be problems either with the other sensors or with the
connections between the sensors and the M-2 transponder unit. Such
messages should be investigated immediately.
UTC clock lost (Information 07)
This message indicates that internal GPS module within the M-2 transponder is
unable to obtain a valid time signal. If this message appears on a regular basis it
may indicate a problem with the GNSS antenna connection, but it is possible for
this message to occur temporarily in certain locations or in extreme weather
conditions where the GNSS module is unable to receive transmissions from a
sufficient number of satellites.
External DGNSS in use (Information 21)
External GNSS in use (Information 22)
Internal DGNSS in use (beacon) (Information 23)
Internal DGNSS in use (msg 17) (Information 24)
Internal GNSS in use (Information 25)
These messages indicate which source of GNSS information is currently in use
by the transponder. The external GNSS information from the ship's main on-
board systems may or may not be augmented by differential correction
information - in which case the messages show "DGNSS" rather than "GNSS".
When the external GNSS signals are not available, the M-2 transponder uses
GNSS information from its own internal GNSS module and the message
changes to "Internal GNSS". This information may be augmented by the receipt
of differential correction data from a beacon receiver or by VHF transmissions
from a base station - in which case the status message shows "DGNSS" and