Chapter 2: Introduction
6
The Inmarsat Fleet Service
Service explanation
2.1.3
The low speed services have a lower tariff than the high speed services,
because the high speed services are high quality audio or high speed data
services that require more bandwidth.
•
The
128 kbit/s
UDI
(Unrestricted Digital Information) service enables 2 x 64
kbit/s or 2 x 56 kbit/s bidirectional transmission of data to and from
terrestrial
ISDN
networks
•
The
64 kbit/s UDI
(Unrestricted Digital Information) service enables the
bidirectional transmission of data to and from terrestrial 64 kbit/s
ISDN
networks. The
56 kbit/s UDI
service is similarly used to make a connection
to 56 kbit/s ISDN networks, which are primarily used in North America.
•
The
Speech
and
3.1 kHz audio
services make it possible to establish high
quality analogue connections of a quality equal to terrestrial analogue
connections via digital networks/switches. The
Speech
service is used for
high quality voice connections, whereas
3.1 kHz audio
can be used to
transfer analogue signals between fax machines and modems with an
analogue 2-wire interface. The 3.1 kHz audio service is transparent, and is
suitable for all analogue applications including secure telephones.
•
The
MPDS service
is a packet data service where the tariff depends on the
amount of data sent and received. This service is a more cost-effective
solution for web browsing, and other applications where there is no need
for constant transmission of data in both directions. It is also suitable for
applications where a constant connection is required, because the user is
no longer charged the “per minute rate”.
•
The
Mini-M voice
service is only for voice transmission. The voice
transmitted over the satellite is subject to a compression process that
reduces the bandwidth to 4.8 kbit/s and consequently reduces the cost.
•
The
9.6 kbit Fax
allows you to send and receive fax messages using a
standard office fax machine. This service replaces the previous Mini-M fax
service. Using this service is usually more cost effective compared to the
3.1 kHz audio service.
