Comar Systems CSB200 Installation And Instruction Manual page 14

CSB200 Class B AIS
LED Indicators
ON
This is a green LED which indicates, when lit, that power has been
connected correctly to the transponder.
Status
This is a green LED which indicates, when lit, that the transponder
hardware has been configured, that the operating software is present,
that the CPU has booted up, the application software is running and
everything is correct.
RX
This is a green LED which indicates when flashing that the CSB200 is
receiving data from other AIS transponders and is outputting this data as
VDM NMEA sentences on the output data ports. If the Green LED is on
continuously the unit has not been programmed with its personalised
data, it will still send received data to the output port but will not transmit.
TX
This is a red LED which flashes momentarily when the CSB200 transmits
its own AIS data.
Timeout
This is a yellow LED which indicates when lit that the transmitter is
prevented from transmitting. Reasons for this include the following:

The transponder's internal GPS receiver is not operating or is not
yet ready

The transponder was unable to transmit an AIS message due to
the channel being already occupied, e.g. by transmissions from
other AIS transponders, or the TX Off function is in operation
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