Mon, 18 Sep 2000

Combating GSM prepaid card theft with SMS alert

By Lim Tri Santosa

BANDUNG (JP): "For all that is good, there is an evil," is a saying that has probably grown more familiar to each of us over the years. It is sad to say this saying also applies to cellular phones, which are inviting targets for thieves. Most mobile phone thefts involve phones stolen from unattended vehicles or by pickpockets.

Related to the theft of mobile phones are prepaid GSM cards, which represent the biggest growth sector in the mobile phone market. These cards can be purchased without ID or legal papers confirming the true owner of the phone, and they protect ones confidentiality because there are no monthly bills.

It is perfect for thieves. So why don't the networks blacklist all stolen and lost phones to send a clear message to thieves that stolen phones will be useless?

Instead, they allow stolen phones, especially those using prepaid cards, to continue to use their networks, contributing more revenue to the fastest growing communications sector.

Further irritation is the expense of purchasing a second mobile phone. Usually the prices of the cell phones you see advertised in newspapers and magazines are heavily subsidized by the cellular network operators, who expect you to buy a new SIM card along with your phone. However, GSM providers also have the capability to block the IMEI code so a stolen handset cannot be used with another SIM card, but they do not do this.

Every digital phone has what is known as an IMEI, or International Mobile Equipment Identification number, which is "burned into" the phone's electronic circuitry. This IMEI number forms part of the phone's "signature" over the airwaves and can be traced by the network. This means that even with a different SIM card inside the phone, the phone's IMEI still identifies the phone's new user in much the same way as car registrations are matched with engine numbers to track stolen cars.

The 15-digit IMEI number is a unique identifier for your handset and is usually printed on the back of the phone, beneath the battery. Some phones will even display your IMEI number on your screen when you dial *#06#.

However, organized criminal rackets exist which specialize in replacing the IMEI microchip in stolen phones to make them completely untraceable and to appear legitimate. It is a public secret you can change your cellular phone's IMEI number in a mobile phone shop.

If you are a postpaid subscriber, you can call your cellular service provider immediately after your phone is lost or stolen. As with credit cards, your provider will deactivate your cellular phone number (SIM number, IMSI number and MSISDN) to prevent your account from being charged with fraudulent calls.

Sorry folks, this does not work for the prepaid service. This leads me to believe the network service providers are not serious in combating cellular phone theft, especially for prepaid card subscribers.

However, there is still one alternative to combat the thieves. The solution is to use the Internet to activate the SMS alert on your stolen cellular phone. Thus, every time the user of your stolen SIM card powers on, a message will pop up informing them the SIM card is stolen and should be returned to you or the police. Undelivered SMS messages will always try to reach the destination number.

You need to connect to the Internet only once to set up the SMS alert, and you can decide what text message will appear, how many times a day and at what time. The real beauty is that only you can switch off the SMS alert, because this free Internet service is password-protected. Although the SMS messages can be deleted from phone card's memory, it will always pop up again.

The thief cannot sell the stolen SIM card, because the buyer will know that it is stolen.

I will take you through the process of setting up an SMS alert for your phone, with the help of two free services, Quios Wireless Service ( and Jaytu Technologies ( Before I begin, it would be better if you have already tried and succeeded in using e-mail alert notification via SMS (my previous article).

One of Quios' free services is Quios Mobile Email (Q-Mail). Q- Mail is a service that allows you to receive an alert on your mobile phone when an e-mail is sent to you. When you register, you automatically receive an e-mail forwarding your account with your Quios ID. So, for example, if your Quios ID is "john", your e-mail forwarding address will be Don't forget to make sure the Q-Mail Notification is on.

When someone sends an e-mail to your Quios account (e.g., an alert is sent to your mobile phone to let you know that an e-mail has arrived. The alert displays the name of the sender and the subject of the e-mail. If the subject is too long for one SMS message, then you will receive additional SMS messages.

Memo To Me is a free, e-mail based, reminder service that allows you to specify one-time or recurring events and automatically reminds you of them using e-mail. You should register first to use this free e-mail reminder service, then you will receive a password that you can use when you want to set up your reminder list. You can choose one-time, daily, weekly, monthly and yearly reminders.

Here is how it works, at least the nontechnological part of it. When you register at Memo To Me, you should use the Quios e- mail address as your legitimate e-mail address, thus every reminder e-mail alert will be sent to your Quois e-mail. Of course, your Quios e-mail address is associated with the stolen cellular phone number.

You can type in as the subject of an e-mail reminder something like: "This is a stolen SIM card, immediately call the police or the true owner of the card, John, at xxxxxxx."

It would be better if you sent the reminder at every hour each day, so the chances are better that every time the stolen SIM card is activated there will be an incoming SMS message.

The thief cannot sell the stolen SIM card, because the buyer will know that it is a stolen card. With nothing else to do, it is possible, somewhat, that the thief will call you to return the stolen SIM card.

After that you can terminate the reminder list at Memo To Me, which is an associated link between Quios e-mail address and the stolen SIM card.

A last message from me: Your SIM card is an essential part of your GSM network service, so please take care of it.