Choosing a Cell Phone: A Guided Tour Through the Cell-Phone Jungle

Summary

This analysis concludes that for the most part, the best cell phone to buy at this time is a digital one based on Code Division Multiple Access (CDMA) technology which can also switch to Analog in areas with no digital service (dual mode). One of the most important advantages of CDMA is how long one can talk before the battery runs down. CDMA has about twice the talk time of TDMA and about four times the talk time of Analog phones (which are essentially no longer available).

CDMA can be identified by knowing which service providers use CDMA: ALLTEL, Cricket Wireless, Quest, Sprint, or Verizon, for example. (There are some exceptions to the use of CDMA especially if you wish to roam throughout the world with only one phone: see the section below on Other Considerations.) There are also web links to a San Francisco Examiner article on choosing cell phones and to a San Francisco Chronicle article on cell-phone quality referenced at the end of this tutorial as well as a web link to an excellent article in Business 2.0 Ezine on third-generation (3G) cell-phone problems.

Analog versus Digital

There are basically two types of cell phone: Analog and Digital. The difference is in the way that speech is transformed into an electrical signal. Both types contain digital circuitry (microprocessors) to manage the switching between cells without which cell phones would be impossible, but the analog phones represent the speech as an analog signal just like the phones which have been around since Bell and Gray. (See The Difference Between Analog and Digital Systems and What Is a Cell Phone?)

Analog cell phones represent a now obsolete technology, have poor speech quality, are subject to noise and interference, and have very very short battery lives. Furthermore there are many new features such as paging which they do not have. In addition digital cell phones have a much higher capacity for the number of users, and the explosion of cell-phone use will soon force the elimination on analog systems since they will not be able to handle the growth. For these reasons it is recommended that new analog cell phones not be purchased and that anyone with an analog cell phone replace it as quickly as possible with a digital one. Thus this article will concentrate only on the choices among digital phones.

The biggest difference that the average user will immediately see between a digital and an analog phone is that the battery life, both stand-by and talk time, is much longer with a digital phone. In addition the speech quality is better and there is much less noise and interference.

TDMA versus CDMA Digital

There are three TDMA systems now in use: North American TDMA, iDEN, and GSM. iDEN stands for Integrated Dispatch Enhanced Network and is essentially a cell phone system which can also serve as a walkie-talkie. Using iDEN, a group can set up a private cell phone network which can function independently outside of a cell. Nextel is the service provider for iDEN, and anyone who wishes these features should consider iDEN. GSM stands for Global System for Mobile communication and is primarily the standard in Europe and much of the rest of the world. Although principally a European standard, GSM is also the system which is used by some North American phone companies.

Advantages of CDMA

All cell phones continually change their power to use just enough to reach the cell, but CDMA needs less power than TDMA digital and much less than analog. For this reason the CDMA talk time is generally longer than TDMA for the same battery size. A way to see the difference in talk time between CDMA and TDMA is to look at the various comparable models on Motorola's Phone-Comparison Page. When one compares equivalent models with equivalent models, the talk time is double on the CDMA phones. Also Motorola makes more CDMA phones than TDMA ones, so the trend is very clear.

Another feature of CDMA Digital is that the CDMA encoding makes it more difficult for an outsider to overhear a private conversation. It is not impossible to listen in, but it requires more technical knowledge and more investment in equipment. Also the required equipment is not sold at most electronic stores.

From the point of view of the service provider, CDMA can support many more users than TDMA or analog (about 3 times as many as TDMA and 10 times as many as analog). This may seem unimportant to a user, but the rapid growth of cell phones probably means that ultimately all cell phones will have to be CDMA to handle the growing number of callers.

Because of all of these factors it is recommended that customers purchase CDMA digital cell phones which works in the 850 MHz bands. It is also important that they purchase a dual mode phone, i.e. one which automatically switches to analog in an area where there is no digital service.

Why Not PCS?

The PCS services are at 1900 MHz. A 1900-MHz cell is smaller than an 850-MHz cell. Because of this, the service provider must have up to 4 or 5 times as many cells to give equivalent coverage, and many have not yet been willing to spend the additional capital investment to get really good coverage.

In addition, for VirtualPBX users there another reason: Sprint, one of the main PCS service providers, does not have the feature "Paging Without Ringing". This means that a VirtualPBX user who wants his digital cell phone to also act as a pager so that he wont have to carry both a cell phone and a pager, can't do it. What Sprint and most other digital service providers can do, however, is send email to a cell phone. VirtualPBX.Com has email notification of new Voice and Fax Mail, and this is becoming the most popular notification method. See the tutorial: New-Message Paging.

Identifying the Type of Service of a Cell Phone

1. ALLTEL - CDMA
2. AT&T - TDMA and GSM
3. Cingular - GSM and TDMA
4. Boost Mobile - iDEN (Pay as you go.)
5. Cricket Wireless - CDMA
6. Nextel - iDEN (a version of TDMA)
7. Qwest - CDMA
8. Sprint - CDMA
9. T-Mobile - GSM
10. Trac Wireless - TDMA and CDMA
11. U.S. Cellular - TDMA and CDMA
12. Verizon - CDMA
13. Virgin Mobile - CDMA

Users with special needs may wish to purchase a different digital cell phone than one based on CDMA.

For example, anyone who wishes to establish a network where their phones are both cell phones and walkie-talkies should consider iDEN.

It used to be that anyone who wished to connect to certain features of the Internet had to consider Sprint or one of the other PCS (1900 MHz) service providers because they included Internet access with some of their phones.

Now, however, at least Verizon, and perhaps some other 850-MHz service providers also offer Internet connection with new cell phones.

In general U.S. cell-phone users who wish to roam internationally cannot do so without changing phones. There are, however, exceptions to this rule. T-Mobile, a national GSM service provider, offers tri-band GSM phones which can roam throughout the world. Cingular (formerly Pac Bell Wireless) does not have world-wide GSM roaming agreements, but a Cingular user may go to a foreign country and purchase a prepaid SIM card. He can then use his phone in that country. Nextel also offers a world-wide service with a phone which is both GSM and iDEN. Because of T-Mobile's and Nextel's world-wide roaming agreements and because the above phones are dual- or tri-band 850 and 1900 MHz GSM, it is possible to roam in the entire world using the phones listed above. A T-Mobile user has the convenience of being able to use his phone in any country where there are roaming agreements, but this is of course more expensive. If one is going to be in a country for long time, it is often better to purchase a SIM card and get a local number.

If you do not wish to purchase GSM service for international travel, it is possible to rent a second cell phone (for example, from CellHire at 1-888-271-1302, from T-Mobile at 1-877-OMNI-2-GO, from RentCell, Inc., from Action Cellular at 1-800-RENT-PHONE or from to the choices in the Comprehensive Rental List). Also see the paragraph below to learn about Iridiums's or Globalstar's solution for the user who has no terrestrial cell service at all or the traveler who goes to such a part of the world.

The Future

Terrestrial cell phones only work in the cities and on the highways. They don't work in the mountains, the countryside, or the third world. For this reason Iridium (TDMA) or Globalstar (CDMA) developed digital cell-phone systems which replace the cells with constellations of satellites. Globalstar or Iridium make it possible for a traveler to carry a single cell phone which works almost anywhere in the world.

Qualcomm and Ericsson are jointly working on a third generation terrestrial cell phone standard which will work anywhere in the world that has conventional cell-phone service. When these systems become operational, it may no longer be necessary to rent or own a second phone when traveling to a different area. There is an excellent and detailed story about Third Generation (3G) Cell Phones by Robert Poe put out by Business2.0 Ezine.

Additional Information

In these articles GTE is now Verizon, and CellularOne is now AT&T.

An excellent article on choosing a cell phone appeared in the February 21, 1999, issue of the San Francisco Examiner:

S.F. Examiner Article: Navigating the Cellular Maze

There is also an article on "dead spots" and "dropped calls" in the November 1, 1999, issue of the San Francisco Chronicle:

S.F. Chronicle Article: Cell Phone Black Holes, Places where wireless callers can't get a connection proliferate throughout Bay Area

For cell phone users outside of the San Francisco Bay Area, the Chronicle article on is most interesting for its statistics on "dropped calls" and "customer satisfaction" which are summarized at the end of the article.

At the very end are comparisons based on a survey by Telephia (not the reader survey) showing: Network Quality Satisfaction, Dropped Calls, Cannot Get a Signal, and Cannot Place a Call in Buildings.

To understand the comparison: Cellular One is TDMA, Verizon is CDMA, Cingular (Pac Bell) is GSM-TDMA, Nextel is iDEN (TDMA), and Sprint PCS is CDMA. To understand the problems that Sprint has, it must be remembered that Sprint and Pac Bell are at 1900 MHz whereas all of the others are at 850 MHz. The 1900 MHz cells are smaller, and there are more transmission problems at the higher frequencies. Sprint also sells dual band/dual mode phones which switch to the 850 analog mode when no digital signal is available, and this helps their problems.

It should also be remembered that Globalstar USA will not have most of these problems since the Globalstar phones do not depend on terrestrial cells but used satellites for their cells. Since the Globalstar phones are tripple mode (Satellite CDMA, Terrestrial CDMA, and Terrestrial Analog) they work as an ordinary CDMA digital or Analog cell phone where the signal is available and as a satellite phone in the dead spots. The only caveat with Globalstar is that the satellite phones do not work in buildings (but the cellular modes do!).

A good comparison of many phones is provided by C-NET's Cell Phone Reviews.