In voice radio certain procedural words are used as an alarm signal. MAYDAY indicates a distress; MAYDAY RELAY indicates a distress relay and MAYDAY received indicates a distress acknowledgement. Normally the frequency used to initiate the distress alert is the frequency used to acknowledge the alert and becomes the control frequency. Coast stations or rescue units may request a change in frequency to facilitate better communications but the distress unit must agree. A coast station hearing 2182 alarm signal or MAYDAY should impose SILENCE on the distress frequency so that the distress message can be heard. Vessels hearing SILENCE MAYDAY should maintain silence on the frequency until the distress is ended or SILENCE FINI is received.
| DISTRESS
| MAYDAY, MAYDAY, MAYDAY
|
| This is … (name and call sign of distress)
|
| DISTRESS INFORMATION (position, etc.)
|
| RELAY
| MAYDAY, MAYDAY, MAYDAY
|
| This is … (relay ship or station)
MAYDAY RELAY
NAME AND CALL SIGN OF SHIP IN DISTRESS
|
| DISTRESS INFORMATION (as received)
|
| ACK
| MAYDAY, MAYDAY, MAYDAY
|
| NAME AND CALL SIGN OF SHIP IN DISTRESS
|
| This is … (acknowledging station)
RECEIVED, MAYDAY
|
Procedures for acknowledging a distress using NBDP telex are the same as voice radio except substitute DE for THIS IS and RRR for RECEIVED.
