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Just as there are several different
types of mobile messaging (SMS, EMS, MMS, etc.) there are also several
different mobile phone standards:
Each mobile phone standard is described below.
AMPS (Analog)
 AMPS is an acronym which stands for "Analog Mobile Phone
Service" or sometimes also known as "Advanced Mobile Phone System". The
AMPS standard was the most prevalent analog mobile phone standard used
throughout the 1980s. (However, it was not the very first mobile phone
standard, hence the term "Advanced" in the name.)
AMPS is still in use today for certain high-reliability
voice applications including GM's On*Star service and certain
very-low-bandwidth industrial data applications. Although there is a data
element to AMPS which is used to send the date, time of day, and other
low-bandwidth data to mobile phones, AMPS phones cannot do text or
picture messaging.
AMPS phones do not support the creation of text
or picture messages and thus AMPS is of no use to IMU.
TDMA: Time Division Multiple Access
 TDMA is an acronym which stands for "Time Division
Multiple Access". It is a digital standard which allows for each cellular
"channel" to be divided into time slots, thus providing a gain in capacity
over AMPS. Given the higher capacity per cell tower and the fact that it
is a digital standard, TDMA was the obvious follow-on replacement to AMPS.
Currently TDMA is highly used in the US and a few other
parts of the world, but its use is quickly being phased out in favor of
GSM and CDMA.
Modern TDMA phones support the creation of text
messaging and even Nokia Smart Messages and thus these messages can be
processed and displayed by IMU.
GSM: Global System for Mobile
GSM is an acronym which stands for "Global System for
Mobile". The GSM standard is the most-used mobile standard in the world,
with the largest deployment being in Europe.
GSM is a digital standard which is internally based on
Time Division Multiple Access (TDMA) techniques. Newer GSM phones also
support digital transmission through GPRS, which allows packets of data to
be sent and received at moderate rates. It is this GPRS extension which
allows new features such as MMS and WAP/web browsing capability.
The GSM standard has been around for a relatively long
time. Its popularity continues to grow because of the addition of GPRS and
integration of cameras, MP3 players and other gadgets into GSM phones.
Because of these additions, this relatively old standard is actually being
phased in within the US.
Modern GSM phones support the creation of text
and picture messages and thus these messages can be processed and
displayed by IMU. In fact, GSM is the preferred standard for use with
IMU.
CDMA: Code Division Multiple Access
 CDMA is an acronym which stands for Code Division
Multiple Access. Of the three digital standards mentioned above, CDMA is
the newest and allows for the highest capacity and highest mobile data
throughput. Theoretically CDMA provides many times the channel capacity of
TDMA. Proponents of CDMA also claim that there are fewer dropped calls
when crossing cell boundaries.
Due to the newness of CDMA and extended standards such
as CDMA-2000 and W-CDMA, the CDMA standard is rapidly growing in
popularity in the US, South America and certain parts of Asia.
Modern CDMA phones support the creation of text
and picture messages and thus these messages can be processed and
displayed by IMU.
NTT DoCoMo
Another standard worth mentioning is the NTT DoCoMo
standard. This standard is found only in Japan. NTT DoCoMo phones are very
advanced and support text and picture messaging. Currently IMU does not
support NTT DoCoMo but Pangolin is working on this and will surely have
DoCoMo support at some point in the future.
Other standards
Aside from the major mobile phone standards mentioned
above, there are other standards that are used far less frequently
including NAMPS, iDEN/Nextel, NMT, TETRA/Dolphin, Iridium and Globalstar.
IMU has no direct support for these standards, but may still be able to
receive messages sent by one of these, provided that the carriers have
inter-operability agreements with GSM or CDMA operators, or provided that
IMU can be directly connected to a message server on one of these
networks.
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