
Manual – 2018F Inmarsat Family NRTs
Unidata Manual - 2018F Inmarsat NRT Family - 09 06 2015.docx Page 9
3.0 NRT LED INDICATOR
The simplest indicator is the red LED which is visible in the window of the unit.
On first power on the LED will be brightly on (not flashing) for 10 seconds indicating the
unit is in the process of being reset. Do not interrupt this initial start-up process. If the
initial start-up is interrupted you should power down, wait a few minutes, and then power
up again.
Slow flashing bright LED. One flash per second indicates the NRT is
establishing a network connection via the internal modem. This process takes
approximately 10 to 20 seconds.
Fast flashing bright LED. 3 to 5 flashes per second indicate the PPP session is
running and the NRT is communicating through the internal modem to the host
server. If the NRT is programmed to hold the PPP session open all the time, i.e.
the always on mode, the LED will continue to flash at this rate.
Slow brief flashing (dim) LED. One dim flash every Scan Interval (typically every
5 seconds) indicates normal NRT operation (sleeping). No communication is in
progress. The NRT has been programmed to log data and will only establish
communications at the defined reporting interval with which it has been configured.
Very occasional bright single flash. This indicates the scheme is actively
logging rather than sleeping at that particular time. If you have a scheme which
has a 5 second Scan rate and a 1 minute Log Interval, you will see dim flashes
(indicating sleep) every 5 seconds (i.e. every scan interval), then one bright flash
on the minute, indicating that a log is in progress. This cycle repeats at the Log
Interval, hence the LED will brightly flash every 1 minute.
When the NRT periodically communicates with the Neon server, the LED will
slowly flash as it establishes a network connection, then
quickly flash while it actually communicates with the Neon server (uploads log
data, downloads its scheme, processes queued commands, etc), then
slowly flash as it disconnects from the network
The durations of each stage will vary according to the telemetry type of the NRT and how
much data is transferred between the NRT and Neon server.
If an NRT has been configured on the Neon server to Auto Cold Boot, then after the 10
second start up illumination, the NRT will immediately start a normal comms cycle, as
previously described, following the normal slow flashing, fast flashing, slow flashing cycle.