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Technology Overview
A number of different standards and technologies
for wireless phones exist. This overview gives you a
brief description of these technologies to help you
understand the differences.
Iridium System
With 66 satellites forming a cross-linked grid above
the Earth, the Iridium system is the first low-Earth-
orbiting (780 km/485 miles high) system for wireless
telephone service. The satellites are close enough
to receive the signals of a handheld device and they
act like cellular towers in the sky—where wireless
signals can move overhead instead of through
ground-based cells.
The Iridium system uses a combination of FDMA
and TDMA signals to make the most efficient use of
limited frequency range (1616-1626.5 MHz). When
the phone is in Iridium satellite mode, it uses GSM
technology. The optional cellular cassettes enable
your satellite phone to access other cellular and
PCS systems.
Cellular
Cellular is the term used to refer to the wireless
phone systems that originated in the United States
and originally operated at the 800 MHz radio
frequency range. The FCC allocated this frequency
range for cellular technology in 1983. AMPS,
NAMPS, GSM, TDMA, and CDMA technologies are
all currently available in this frequency range. In
North America there is a maximum of two cellular
operators in each market. These operators are
referred to as the Wireline (landline phone
company) and the Non-Wireline carrier.
Welcome!
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