JP 3-50 National Search and Rescue Manual Vol I - US Navy

4. FAA Domestic Teletype Networks, operated extensively within
the United States, primarily for ATC service. They carry
information concerning missing or overdue aircraft. ARTCCs
and FSSs work directly with RCCs.
5. Teletypewriter Exchange (TWX), a commercial method of
establishing direct communications with subscribers within the
United States and Canada, connecting subscribers through a
commercial switchboard. The switchboard can also connect with
international TELEX systems.
6. Teletype (TELEX), an international commercial service similar
to TWX, which in some foreign countries also serves domestic
needs. While in some countries the various TELEX systems
provided by different international companies interconnect, it
is possible to have two or three different and separate
systems. In such cases, the use of TELEX for SAR can be
complicated.
7. Radio Teletype (RATT), a generic term for teletype circuits
which use radio connection instead of cable or landline. They
may be integrated with some of the systems described above or
they may be special purpose. More and more ships and aircraft
are becoming equipped with RATT. SMCs may find it convenient
in many cases to use a RATT circuit for the control channel
during a mission.
8. NAVTEX is an internationally adopted, automated system for
instantly distributing marine navigational warnings,
meteorological information and search and rescue information
to approximately 200 nautical miles offshore.
9. INMARSAT which allows direct TELEX service to and from
INMARSAT-equipped vessels. Priority is given to distress and
related SAR communications.
C. Telegraphy used in SAR communications is usually
radiotelegraphy between fixed stations and ships. It is most often used
with large ships at sea through a coast radio station.
D. Facsimile (by either cable or radio) is used for transmission
of a picture, and is most often used to transmit charts, such as weather
maps.
E. Data Link, used in several contexts in communications,
generally indicates communications circuits designed for transmitting
raw data from one place to another. They are most useful when
transferring data to and from computers.
330 SAR MISSION COMMUNICATIONS
A. The SAR Coordinator should establish and publish in the SAR
plan the frequencies available for assignment as control, on scene,