The Cell Phone Handbook: Everything You Wanted to Know about Wireless Telephony (But Didn't Know Whom or What to Ask)

The Cell Phone Handbook: Everything You Wanted to Know about Wireless Telephony (But Didn't Know Whom or What to Ask)

by Penelope Stetz

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Cellular phones have gone from a "gee whiz" curiosity to an indispensable communications link for more than 70 million U.S. subscribers. Despite cell phones' enormous popularity, it has been difficult to get reliable, objective information on which to base purchases and maximize performance. Until now. This book will answer questions such as:
  • What's the


Cellular phones have gone from a "gee whiz" curiosity to an indispensable communications link for more than 70 million U.S. subscribers. Despite cell phones' enormous popularity, it has been difficult to get reliable, objective information on which to base purchases and maximize performance. Until now. This book will answer questions such as:

  • What's the difference between analog and digital cellular, and which is best for me?
  • What's the difference between GSM, TDMA, PACS, and CDMA?
  • Which carriers are available in what cities, and how do I choose one?
  • What is PCS, and how is it different from regular cellular?
  • How does the service by Nextel fit into the picture?
  • How do I transmit fax, e-mail, and data over cellular?
  • How do I know what rate plan is best for me?
This book will give you a solid understanding of wireless technologies so you can make an informed purchase decision the next time you buy wireless equipment or services. You will also get an insider's view of how the industry works and where it's headed.

About the Author:

Penelope Stetz has worked in the wireless industry for over ten years selling cellular phones directly to end-users. As one of Motorola's top cellular salesmen, she was nominated in 1993 for Salesman of the Year for all Pan American Cellular Sales. She also helped develop Motorola's Data-on-Cellular training manual, video and CD-ROM as contributing editor. Today, Penny operates her consulting firm, PhoneTech Wireless Consultants (, and resides in Euclid, Ohio.

Editorial Reviews

Offers general readers objective information on which to base cell phone purchases and maximize performance. Traces the history of cellular phones, explains how wireless telephony works and how to acquire wireless equipment and service, and discusses essentials of roaming, fraud, using wireless phones for data, and accessories. Includes a chapter of frequently asked questions, plus many appendices on manufacturers, market areas, and carriers. Annotation c. Book News, Inc., Portland, OR (

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Aegis Publishing Group, Ltd.
Publication date:
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5.55(w) x 8.51(h) x 0.77(d)

Read an Excerpt

Chapter 5: Fraud


What is it? How do the thieves do it? Although there are different types of wireless telephony fraud, the most prevalent is cloning of an analog cellular phone. Here's how it works. A thief uses special scanning equipment to listen for your mobile phone number and ESN to be transmitted to the carrier (which occurs when you turn on your phone, when you make a call, or any time your phone autonomously registers). Then he reprograms the information into an older analog phone. Only phones manufactured prior to 1995 have ESNs that can be reprogrammed, The thief then sells the "cloned" phone, and the buyer uses the phone until it stops working. Cloned phones are typically used outside your home market because the local carrier can easily detect when two phones with the same information are being used on its switch at the same time.

You know you've been cloned when you see an outrageous phone bill, where your mastery of space/time travel is evidenced by the fact that you placed roaming calls from two different markets at the same time! It is also obvious to the carrier that your phone was cloned; it can recognize the patterns. The carrier credits you for the fraudulent charges, which then become a fraud write-off to the carrier. You are issued a new phone number, and your phone is reprogrammed with this new number. This breaks the mobile number/ESN combination by matching a new mobile number to your ESN and renders the old mobile number/ESN combination useless. If keeping your mobile number is important to you, see if you can arrange to have your ESN changed.

The FCC made cloning illegal, and, in 1995, it also made altering theESN by anyone other than the manufacturer illegal. Now, the government has taken another step to crack down on cloning. In the spring of 1998, the Wireless Telephone Protection Act (H.R. 2460) passed, making it illegal to "knowingly use, produce, traffic in, have control or custody of, or possess hardware or software, knowing it has been configured for altering or modifying a telecommunications instrument so that such instrument may be used to obtain unauthorized access to telecommunications services." This means that both the customers who are buying illegally altered equipment, as well as the people who actually do the cloning, are subject to prosecution. First-time convictions are punishable by fine and/or imprisonment up to 15 years. Second convictions are punishable by fine and/or imprisonment up to 20 years.

Fraud Prevention Measures


The magnitude of fraud charges written off by carriers in the United States exceeds $1 million a day! Carriers have taken proactive approaches to reduce fraud write-offs, such as implementing usage profiles. This is a measure that raises a flag if your usage deviates from your established profile. Say, for example, you usually don't roam, or very little, and your normal usage averages 10 minutes a day. If your phone is used 60 minutes a day in a roaming market, you will probably get a call from the carrier asking if the usage is legitimate. If the carrier can't reach you, your phone number may be suspended, requiring you to call your service provider to get your phone working again. Profiling isn't limited to roaming activity. It applies to usage in your home market, as well.

Radio frequency (RF) fingerprinting

In addition to profiling, the carriers are implementing RF fingerprinting (which is switch dependent) and authentication (which is phone and switch dependent). With RF fingerprinting, each wireless phone has a unique and distinguishable RF signature. Cell site RF fingerprinting units build a wireless phone RF fingerprint of your phone by collecting data from several transmissions. This RF fingerprint is stored at the MTSO. Then, all subsequent calls you place are validated with the stored RF fingerprint information to determine if you are a legitimate subscriber. This validation process takes place before the call is actually processed so that a thief using your mobile number/ESN combination in another phone will not be able to place a call.


Authentication is being implemented on analog equipment, but it is built into digital systems. Authentication uses an A-key, which is 26 characters in length. Only the phone and the switch know the A-key. Think of it as a numeric version of your mother's maiden name. If only you and I know your mother's maiden name, and I ask you what the fifth letter is, you can tell me. A thief may have your mobile number/ESN combination, but as the Akey is never transmitted, he is unable to obtain this vital element to respond to the challenge and, therefore, is unable to place a call. Because the Akey is 26 characters long and contains numbers, the switch has an endless variety of challenges for the phone. The challenge occurs when you initiate a call and takes only seconds to complete.

PIN codes

A fraud deterrent that has been around for a few years is the use of a PIN code. PIN codes can be used several ways. Some carriers require you to dial the PIN code immediately following your outbound number each time you place a call, so your dialing sequence will be: 1-800-555-1212 SEND (stuttered dial tone) 1234 (PIN code) SEND.

Other carriers require you to "open" your phone use by dialing *560-XXXX (the Xs are your fourdigit PIN) SEND. Then you "close" your usage when you are finished making calls by dialing *56 SEND. Sometimes carriers require you to establish a PIN code that will be used only when you roam. Usually, you are prompted for the PIN code the first time you try to place a call in the roaming market. Depending on the market and the relationship between the carriers, this may be the only time you are prompted to enter your PIN code for the duration of your visit. On the other hand, you may need to reenter it with the first call you make each day you are roaming.

Subscriber Fraud

As fraud-deterrent measures are implemented in analog cellular and as digital service becomes more available, cloning is less accessible to the thief. A growing kind of fraud being perpetrated on wireless carriers is subscriber fraud. In this case, someone subscribes to a carrier for wireless service with no intention of paying for his or her airtime charges. This is accomplished through the deliberate use of invalid or false credentials such as name, address, social security number, tax ID, etc.

What Can I Do to Prevent or Reduce My Chances of Being Cloned?

There are several steps you can take to reduce or prevent your chances of being cloned. First, pay attention to your phone bill. Sometimes cloning fraud goes on for months, gradually building up. Noticing fraudulent activity on your phone bill and report it promptly should reduce the amount of fraud charges, but won't necessarily eliminate the need to change your phone number. Second, if you are replacing your old phone and buying an analog phone, ask if it is capable of authentication and whether or not the carrier supports authentication. If it fits into your budget, consider buying a digital phone, which all but eliminates your risk of being cloned.

More information about carrier solutions to fraud can be found at CTIA's Web site ( /professional/fraud)....

What People are saying about this

Penelope Stetz
The wireless telephone industry is moving at a very rapid pace. In the past twelve months, as this book was becoming a reality, I've seen some terrific reductions in the cost of wireless phone usage. I am excited at what the future of wireless telephony has in store for us.

In the chapter on Wireless Equipment and Service, you'll find interactive guides for buying equipment and for choosing an airtime service provider. If you want to change carriers, you can compare the competitive rate plan to your existing plan using the Rate Plan Analysis. That way, you'll sign up for a plan that's right for you.

I've included 98 pages of appendices. In addition to some useful lists of coverage information, there are addresses and Web sites for handset manufacturers, carriers, satellite companies, and 36 other contacts relating to wireless telephones.

There has never been a better time to get a wireless phone. There are lots of options for all types of users. I hope this book makes buying and using a wireless phone a more gratifying experience for you. You can find updates on URLs listed in the book at The Wireless Whiz Web site (

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