Associated Press

Q I subscribed to a new cell phone plan after I let my previous one expire. I still have the phone, but am going to get a new plan from a different company. Can I just have my new phone reprogrammed? If not, what can I do with the old one?

A Besides using it as a paperweight, your phone might still have some life left in it, but frankly, it depends.

Cell phones are essentially nothing more than very fancy radios with lots of gadgets. Like radios, they use certain frequencies — or spectrum — to kick communications back and forth to other cellular phones and, of course, to traditional phones, too.

But the difference between one phone and the next, as well as the company that offers the service, hinges first on the type of technology that company uses to let its phones communicate.

There are three major technologies — CDMA, TDMA and GSM — that cell companies use to power their networks. If you’ve just wrapped up a yearlong plan from one company and the phone you’ve got is CDMA-compliant, chances are you could have it reprogrammed on another provider’s network if it uses CDMA. The same applies to phones and companies that use the TDMA or GSM networks.

However, if you’ve got a phone that’s for GSM use only, say an Ericsson T28, it’s not going to work on a CMDA network. Similarly, a Nokia you got when you signed up for service with Verizon Wireless may not be compatible with the services offered by Cingular.

There’s another variable — each provider has its own rules and regulations.

According to Sprint PCS’s Nancy Sherrer, "For security and quality, Sprint PCS only allows those devices that it has tested and approved on its network. So a customer leaving a competitor and activating Sprint PCS service could not reprogram the existing phone."

Even though it may appear that similar carriers — whether it’s Verizon or VoiceStream or Cingular or AT&T Wireless — have near similar technology or even the same phones, that doesn’t mean they’re compatible.

There’s usually a slight difference in each model, although they might be made by the same manufacturer, that is proprietary to the cellular company in question.

But in the competitive world of cellular service, it’s easy just to get an entirely new phone when you sign up with a new plan. The providers usually offer inexpensive — or even free — phones, with an array of options and choices. Given the advances in technology, a new cell phone will also give you more features from the voice mail to caller ID, to Internet-browsing and instant message, something your older phone may not have.

If keeping the old Qualcomm is absolutely paramount, then call the provider you’re thinking about signing up with and ask them, or take it to a cellular store and ask them to see if it can be programmed into their network.

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