NBDP –TOR
- SITOR
NBDP – RADIOTELEX:
RTTY – RADIO TELE TYPE
SITOR – SIMPLEX TELEX OVER RADIO
TOR – TELEX OVER RADIO
NBDP – NARROW BAND DIRECT PRINTING
TELEGRAPHY
SELCALL NUMBERS:
Coast
station – 4 digits
Ship
station – 5 digits
OCC – the called subscriber is engaged
NC – no circuit are available at the
moment
ABS- called subscriber is absent or
office is closed
CI – conversation impossible
CFM – confirm/ please confirm
BK –break
DER – out of order
GA – go ahead
MOM – wait/waiting
RPT – repeat
BRK+
Break the circuit
MSG – ready to receive the message
OBS – transmitting weather rep[orts (wx)
What is NBDP?
Narrow
Band Direct Printing
What are the two methods of
communications used in NBDP?
ARQ
and FEC
What is ARQ? Explain
One
–to-one communication
ARQ
– It is a error detection and error correction method
In
ARQ mode,
BOTH
SATIONS (on communication) transceivers
are ON position
Messages
are sent in packets
Each
packet contains 3 characters
If
the receiving station not received correctly…that means..
If
there is any error at the receiving end,
It
will ask for repetions automatically
And
This will be maximum 31 repetetions
What is FEC? Explain
One-to-several
OR one-to-many communication
In
FEC mode,
The
transmitting station and other stations (on communication) transceivers are
ON
position
In
transmission of message,
Each
character is repeated TWICE
\and
Missed
character (if any) will be printed as *
Type of aerial used?
Quarter
wave aerial (SSB aerial)
Speed of transmission?
ARQ
– 50 bauds FEC – 100 bauds
Frequency covered?
MF
marine band and HF marine band
What is baud?
Unit
of speed of digital transmission
What is the ID used in NBDP?
SELCAL
How the charges are calculated in NBDP?
ON
DURATION
What is the bandwidth of NBDP?
170
Hz
(85
Hz + 85 Hz)
