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

Inmarsat-B PC Fax and Data Calls

Where Inmarsat-A requires you to ask for a special 'companders-

out' channel for fax and data calls, Inmarsat-B handles this requirement

differently. Your Inmarsat-B unit will have a separate 'fax port', and a

'data-port' - each with it's own, independent Inmarsat-B ID.

When sending/ receiving fax messages, the ID used by the 'fax

port' on your equipment tells the shore-side LES system that it is a fax

call (and similarly when a data call is being made, using the 'data port'

ID). This allows the (digital ship-borne and shore-side LES) equipment

to automatically configure itself for optimum performance.

Your equipment supplier should have 'configured' each 'port' on
your ship's equipment according to whether it is a telephone, telefax, or
data port.

For data transmission/reception, (e.g. Internet - including e-mail
access), you may have to set-up your computing software yourself, if this
was not provided as part of a complete communications system at the
time of Inmarsat equipment installation.

Internet Access, & Internet Electronic Mail (e-mail)

Some Land Earth Station Operators (LESOs) provide special

facilities for accessing the Internet, using Inmarsat-A, Inmarsat-B and
Inmarsat-C (GMDSS) equipment. Non-GMDSS equipment (including
Inmarsat-M and Mini-M) can also be used to access the Internet.

You can use the Internet to:

• Access information using the 'World Wide Web' (www) - including
  weather charts, or up-to-date radio/satcom service information_


• Send/receive e-mail messages.

Inmarsat-A and Inmarsat-B can be used for both the above
purposes. Inmarsat-C can only be used for e-mail (not direct 'web' access)_

Inmarsat-M and Mini-M can be used for both purposes - though
the speed of data transmission, being much slower than Inmarsat-A and
Inmarsat-B, tends to make 'web' access more costly - due to the extended
time 'on air' to download information.

Computers and Internet access/ e-mail software has to be set-up
differently for different manufacturer's Inmarsat equipment, and for
gaining access to the Internet through your chosen LES.

MARINE COMMUNICATIONS 65