Cell Phone Modes

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 digital 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). A phone that works on one system won't work on another. What's more, a phone that works on any of these systems won't work on the standard analog format used by all North American carriers.

That's 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 phones

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 (This area is usually immediately around a metropolitan area, as digital coverage has not expanded into rural areas, yet). 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 phones

Dual-mode phones work on two different types of networks. Typically, a dual-mode phone will work with one digital format and frequency (e.g. 1900 MHz CDMA) and with analog. This gives the phone the capability to be used just about anywhere. Whenever the digital network is not available, the phone can automatically switch over to an analog system.

Dual-band phones

A dual-band phone operates on two different frequencies, but uses the same signal format. (e.g. 800 MHz and 1900 MHz CDMA) They are useful for carriers who operate networks using different frequencies in different locations. Dual-band phones are not frequently used in the United States.

Tri-mode phones

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. AT&T Wireless Services uses 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 which type of phone do you need?

It all depends on your usage: If you're only going to need your phone within your local calling area, or in other cities that offer the same digital signal format and frequency as your carrier, you can use a single-mode phone. If you will be traveling a lot or spending a lot of time in areas where digital service isn't available, a dual-mode phone makes more sense. Keep in mind that they will cost more than a comparable single-mode phone. The carriers who use tri-mode phones (AT&T Wireless Services is one), tend to offer only tri-mode phones. Quartz countertop - countertopsguide.net . websites to buy music for mp3 . Acheter v i a g r a naturel traitement efficace . wholesale VoIP carrier