NT-2000 REF Manual
Theory of Operation
8-2
8. Summarized Theory of Operation
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8 . 5 .
N AV T E X Re c e i v e r – G e n e r al
A NAVTEX receiver that complies with the relevant IMO resolutions and regulations for
wheel mark certification is programmed to automatically receive and display/print a
message, and avoids a repeated reception of the same message by checking the ID and
numbering of each message. Using the ID and message type data attached to each
message, the user can also program the receiver to reject certain transmissions and
message types that are not of importance while in the current area, except for SAR and
other urgent warning messages classified as type D messages. An audible and visual
alarms are automatically triggered upon reception of such a message. To silence the
alarm, the user must manually acknowledge the message arrival. Received messages
are either printed on paper (for a receiver with a built–in printer) or displayed on a
screen with memory for storage and retrieval (for a receiver with an LCD screen).
8 . 6 .
T h e N T – 2 0 0 0 / D E B E G 2 9 0 2 N AV T E X R e ce i v e r
The NT–2000/DEBEG 2902 receiver has two built–in receiver, with the first receiver
devoted to receiving 518 kHz broadcast and the second receiver receiving either 490
kHz or 4209.5 kHz signal as selected by the user. Received messages are displayed
across an 8–inch liquid crystal display (LCD) and stored permanently or temporarily as
specified by the user. Up to 200 messages, each with an average of 500 characters,
received on the first and second receivers are separately stored and then automatically
erased from memory 60 hours after the time of reception on a first–in–first–out basis.
However, up to 25 messages can be protected against automatic erasure, and are stored
in a separate area of the non–volatile message memory, in which case an additional 50
new messages can be stored in memory.
When a transmission occurs on the first and second receiver frequencies at the same
time, the equipment receives both signals, displaying the first receiver message while
storing the second receiver message in memory for later retrieval. An appropriate
caution message shows up in the screen bottom prompt line to indicate the reception of
a new NAVTEX message on the second receiver.
Reception of a type–D message activates the audible and visual alarms. The received
message text is shown in red, making it easy to discriminate it from navigational and
weather warnings. The audible alarm also sounds differently to indicate that a type–D
message has been received. The alarm can be acknowledged remotely by an INS device
connected to the RS–422 port on the rear panel.
The stored messages can be output via three interface ports mounted on the rear panel
for IBS/INS or other onboard applications The user can specify the ID, frequency and
type of the messages you wish to output. An optional printer can also be plugged in to
print the current message in real time or those recalled from the non–volatile memory.
*
1
: Global Maritime Distress and Safety System
*
2
: International Maritime Organization
*
3
: International Telecommunications Union
*
4
: Safety of Life at Sea
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