Ian Waugh - A Mariner\'s Guide to Marine Communications

Inmarsat-M and Mini-M installations

Inmarsat-M and Mini-M offer the same range/standard of services,

but with the different coverage areas shown in figure 8.8. Services

available are:

Automatic telephone service.

• Fax service (at speeds of 2.4kbit/second - about 25% of the speed
  expected on Inmarsat-A/Inmarsat-B).
  A data (including e-mail) service - also at 2.4kbit/second.
  The main components of an Inmarsat-M/Mini-M installation are:
  1 The Antenna: as with other Inmarsat antennas it should be mounted
  clear of obstructions and not at the same level as radar/radio
  transmitting antennas.
  2 Main Communications Unit: may be hidden behind panelling or bolted
  to the bulkhead. Some Inmarsat-M units have a Distress Button on the
  MeU. Others are operated entirely from the handset keypad/screen.
  3 Telephone Handset: a minimum of one telephone will be fitted.
  Inmarsat-M units have up to four (4) interfaces that can be used for
  telephone, fax or data inputs and are used, typically, as two telephone/
  one fax/one data (computer) interface. Mini-M units have up to three
  interfaces for telephonelfax/data.
  4 Facsimile (fax) Machine: optional. Fax operates at 2·4kbitlsecond
  on Inmarsat-M and Mini-M - about 25% of the speed oflnmarsat-A/
  B and not, therefore, economical in call costs.
  5 and 6

Computer and Printer: for data communications (including e-mail).

Data, like fax, operates at 2·4kbit/second and is not economical for

large amounts of data but can prOVide adequate e-mail

communications where arrangements have been made with a
particular LES operator for e-mail forwarding.
Some Mini-M terminals may be configured to operate through
only one LES in each Ocean Region (satellite). Inmarsat-M terminals
usually allow you to choose a LES for each call, though a preferred
LES is normally programmed, for each Ocean Region/satellite.
Some Inmarsat-M terminals have a telephone distress button,
similar to (though less sophisticated than) those on Inmarsat-B
installations. Inmarsat-M and Mini-M should allow you to use the same
special access (two digit) safety codes (32, 38, 39 etc) as are available on
Inmarsat-A, Inmarsat-B and Inmarsat-C services.

172 THE NAUTICAL INSTITUTE