Alarm Signal:

Radio telegraphy alarm signal comprises of 12 dashes, each of 4 seconds long. Transmission to be made on 500KHZ and repeated if necessary. This alarm will activate ship’s auto alarm equipment and draw attention of the operator and bridge watch keepers.

What is distress signal and who can send it?

Distress signal is SOS (dit dit dit dah dah dah dit dit dit) which indicates that a ship, aircraft or other vehicle is threatened by grave and imminent danger and requests immediate assistance. Distress signal and distress alarm signals shall be sent only on the authority of master or person responsible for the ship, aircraft or other vehicle.

Distress Call:

- the distress signal SOS sent three times;

- the word DE;

- the call sign of the mobile/aircraft station in distress, sent three times.

Distress call shall have absolute priority over all other transmissions. All stations which hear it shall immediately cease any transmission capable of interfering with the distress traffic and shall continue to listen on the frequency used for the emission of the distress call.

Distress Message:

- the distress signal SOS

-the name, or other identification, of mobile station in distress.

-particulars of its position

-the nature of the distress and the kind of assistance desired.

-any other information which might facilitate the rescue.

As a general rule, a ship shall signal its position in latitude/longitude using figures for degrees and minutes, togather with one of the words NORTH or SOUTH and EAST or WEST.

Distress call & Message transmission procedure:

a) the alarm signal; followed in order by

b) the distress call and an interval of two minutes

c) the distress call

d) the distress message

e) two dashes of ten to fifteen seconds each

f) the call sign of the station in distress.

The distress call followed by the distress message shall be repeated at intervals especially in the silence periods.

Acknowledgement of receipt of distress message:

- the distress signal SOS

- the call sign of the station sending the distress message, sent three times

- the word DE

- the call sign of the station acknowledging receipt, sent three times

- the group RRR

- the distress signal SOS

End of distress traffic:

When the distress traffic has completely ceased on a frequency which has been used for distress traffic, the station which has controlled the distress traffic shall transmit on that frequency a message to all stations (CQ) in the following form indicating that normal working may be resumed:

- the distress signal SOS

- the call CQ , sent three times

- the call sign of the station sending the message

- the time of handing-in of the message

- the name and call sign of the mobile station which was in distress

- the service abbreviation QUM

Relay of distress message by station not itself in distress:

Mobile station or coast station which learn that a mobile station is in distress, shall transmit distress message in any of the following cases:

a) when the station in distress is not itself in a position to transmit the distress message.

b) when the master or person responsible for the ship or aircraft not in distress, or a person responsible for the coast station, considers that further help is necessary.

c) when although not in a position to render assistance, it has heard a distress message which has not been acknowledged.

Under above circumstances, following actions will be taken by the station not itself in distress:

- the signal DDD SOS SOS SOS DDD

- the word DE

- the call sign of the transmitting station, sent three times.

- distress message of the station in distress with details.

This call shall be preceded by the alarm signal, followed by a two minute interval when necessary.