While digital
wireless phones have dramatically improved cellular call
quality, there are drawbacks. They don't work everywhere and
they don't work with every wireless carrier. This is why it is
important to know what type of phone your wireless provider
will support on their network. Believe it or not, not every
phone will work on every system. Each carrier's digital
network uses one of three formats, Code Division
Multiple Access (CDMA), Time Division
Multiple Access (TDMA) or Global System
for Mobile (GSM).
Now here is
where the terms "mode" and "band" come in.
Recognizing that many people will want to use their phones
outside of the major cities where digital coverage is in
place, most manufacturers offer phones that will work with
both digital and analog networks (modes), as well as at
different digital frequencies (bands).
Single
Mode- A single-mode phone will work only with a particular
signal format and frequency. For example, a phone that
operates only on an 800 MHz CDMA network is considered
single-mode. Single mode phones are best for people who do not
plan to travel outside of their home calling area. The phone
will not work when the user leaves the coverage area. The
phone will work, however, in a different city that has a
network that uses the same signal format and frequency.
Dual Mode-
A phone that has dual-band capability can switch
frequencies. This means that it can operate in both the
800 MHz and 1900 MHz bands. For instance, a dual-band TDMA
phone could use TDMA services in either a 800 MHz or a 1900
MHz network.
Dual Band-
In cell phones, "mode" refers to the type of transmission
technology. A phone which supported both AMPS (analog) and
CDMA (digital) could switch back and forth as needed. It is
important to remember one of the modes is AMPS (analog) which
gives you wireless service if you are in an area which does
not have a digital signal. Examples would be rural areas of
the country, mountain regions, or just areas which currently
are not served with a digital signal.
Dual Band
and Dual Mode- This is the best of both worlds as the
phone would switch between frequency bands and transmission
modes as deemed necessary. Phones which support these changes
does this automatically. Keep in mind there may be a few
"dead" spots which read "No Service,"
however this is easily overcome by just relocating your
position geographically.
Tri-Mode-
Technically speaking, a tri-mode phone could be called a
dual-band, dual-mode phone. A tri-mode phone will work on two
frequencies with one digital format (e.g. 800 MHz and 1900 MHz
TDMA), and it will also be able to access analog networks.
Verizon and Sprint for example use tri-mode phones, since
parts of its network operate at 800 MHz and other parts
operate at 1900 MHz. The phones are also designed to work on
analog networks whenever digital coverage is not available.
So what is
the right phone for you? If you plan to stay within your
local "home" area, then a single mode phone would
work. However, if you plan on occasion to leave your home
area then you will definitely need to invest in a Dual
Mode Dual Band phone. This will allow you to have continued
wireless coverage outside of your home area. Depending on what
type of service is available, your Dual Mode Dual Band phone
will make the switch automatically to keep you connected.
Finally, if you happen to travel almost exclusively and are
away from your home area, then consider the Tri-Mode phones
which allow you to access the nation wide coverage areas with uninterrupted
digital service. Please contact your current wireless provider
for further details and plan coverages. The map below shows an
example of the National Coverage by Verizon Wireless.
