As you learned in How Cell Phones Work , wireless phones are basically duplex radios that operate using either analog or digital signals. Analog has been around the longest and has the widest coverage. Analog phones operate in smaller cities and rural areas where digital service is not yet available. Digital networks are growing fast in many of these areas, and since they were not the first in a given market, their per-minute rates tend to be lower. And, despite their limited availability, digital plans are a must if you plan on taking advantage of newer features, such as caller ID, voice mail, e-mail, or searching the Internet.
Some providers offer both analog and digital service to provide a wider coverage area.
You can use both if you buy a dual-mode phone . These phones can switch from digital to analog on the fly if the digital signal is dropped. This means that you don't have to worry about losing important calls if you're traveling through an area with gaps in digital coverage, and you can still use the Web. The two digital choices, digital cellular and PCS, use different frequency bands on the radio spectrum. Which frequency bands are offered and which access standard is used by a carrier will limit your choice of phones.