23
Example of FEC Transmission
Assuming the GMDSS telex terminal is in Standby and the radio is
set up to telex mode and to the desired frequencies following a DSC
Distress alert call, proceed as follows:
Press
Call FEC. The printer responds by printing:
Broadcast FEC or Selective FEC (B/S)?
Press the ‘B’ key. The printer responds by printing:
Broadcast FEC call 1997-10-05 12:30:23, Tx 2174.5 kHz
The transmission starts, the ‘Tx’ keyboard indicator starts flashing
and the control unit display indicates that the transmitter is delivering
RF output to the aerial. When the phasing sequence (including
carriage return, line feed, letter shift) has been transmitted the ‘Tx’
lamp shines steady light and the printer responds by printing:
>
The communication to follow must be in accordance with the
procedures specified for distress traffic and contain:
•
the distress signal ‘Mayday’;
•
the words ‘this is’;
•
the 9-digit identity and call sign or other identification of the
ship,
•
the ship’s position if not included in the DSC distress alert;
•
the nature of distress;
•
any other information which may facilitate the rescue.
The connection is terminated by pressing the
Break key. After a few
seconds transmission stops, the Standby keyboard indicator lamp
goes on and the terminal is ready to receive.
Example of ARQ Transmission to a
Coast Station
When the GMDSS telex terminal is on, indicated by the ‘Standby’
keyboard indicator lamp, and the radio is set up to the desired
working channel (and, if requested by the coast station, free signal
can be heard in the speaker), press the
Call ARQ key.
The printer responds by printing:
Enter ARQ call code:
Type in the call code, e.g.: 0832
If ok, press carriage return (<- Enter), (otherwise press
Call ARQ
again).
The printer responds by printing:
ARQ 0832 call, 1997-10-05 12:45:10,
The transmission starts, the ‘Tx’ keyboard indicator lamp starts
flashing and the control unit display indicates that the transmitter is
delivering RF output to the aerial. When successful connection has
been established the ‘Tx’ keyboard indicator lamp shines steady light
and the printer responds by printing:
>
The exchange of answer-backs is initiated by the coast station. The
answer-back code of the called station is printed:
0832 AUTOTX DK
followed by a go ahead indication and a traffic direction change:
GA+?
If direct connection with a land telex subscriber is wanted, type:
dirt
where 54321 is the telex number of the subscriber. The coast station
responds with:
MOM
Dialling follows automatically, and simultaneously the number
selected is sent to the ship:
54321
When the connection is ready, the time, answer-back, “via Lyngby
Radio” and “MSG+?” is sent:
97-10-5 12:46
54321 ZYXW VIA LYNGBY RADIO
MSG+?