I often get calls from friends/family about how their existing wireless company finally did it, making them want to move to another carrier. I explain to them that I wish them luck, as all of them have the same problems, but that is not the point of today's discussion. Instead I am going to focus on the next question they all inevitably have, "why can't I take my phone with me????"
Well, the answer to that is pretty simple, yet technically complex. The main reason is that you never really bought the phone in the first place. If you remember back to when you signed up for the service, more than likely you got a great deal on the phone. No, I am sorry to say that the phone you paid a penny for is not actually yours. This practice, common to all wireless companies in the world, is known as subsidizing. They actually pay hundreds of dollars for that phone, only to discount it to you so that you will want to be with their service. In a sense, they are allowing you get a cool phone for nothing, since they make money on your wireless service, not selling you the phone. This viscous circle has every consumer in the world expecting cheaper and cheaper phones that do more and more.
So you may have possession of the phone, but the wireless company still "owns" it. What the companies do is to place special lock codes in the phone to prevent some other company from modifying the phone to work on a different network. For GSM companies, this is known as SIM locking; CDMA companies this is known as Master Subsidy Lock code.
The GSM code prevents SIM cards from other companies to work in hardware originally sold by another company. When looking on eBay, in the description you will see either unlocked phones or the company the phone works for. Unlocking the GSM phone is not too complex and if you google the world, the software and methods can be purchased, or even service offered for a fee. I know many people who do this for a living.
CDMA phones work a bit differently. They find systems based on a Preferred Roaming List (PRL), or a small file in the phone, that tells the phone what systems are good and what are bad. To make a Sprint phone work on Verizon, Cricket or any other CDMA company one would just need to copy that company's particular PRL into the phone. The phone really doesn't care what company's network it is on, it just has to follow the instructions from the PRL.
So why can't you do these things easily? Well, the Subsidy is very costly to wireless companies. The more they subsidize you in the beginning, the longer they need you to be a customer to break even. This is why companies like Sprint have two year contracts to get the best price on the phone. On the contrast, companies like MetroPCS who sell large all you can use plans don't have contracts so you tend to pay more for the handset. Compare a Samsung Camera flip on MetroPCS website at $219 versus $59 on Sprint with the two year contract. The wireless companies make money on your monthly rate plan so they are willing to lose money to get you as long as they see you will be there for two years at a certain revenue stream per month. That is why there is a fee for canceling early at about $150, which is magically the same as the difference in the cost between these two carriers.
So the last thing Sprint wants is you to get one of their phones for $59 and then activate that phone on MetroPCS' network. They would be losing money faster than they already are. To prevent that, most CDMA companies use a Master Subsidy Lock code to prevent people from writing over their PRL with another companies. This is the code they also use to program the phone with when you call and activate. Since this is the same code, many started using One Time Subsidy Lock codes to program the phone number, keeping the Master secret. The only time the Master Code would then be needed is if the software needs new software or an updated PRL. These codes are 6 digits in length and the phone usually will power off if you put in the wrong code, preventing you from trying all 1 million possible numbers. Verizon and some other CDMA companies didn't particularly protect these and used either 6 zeroes or '123456' as their Master Codes, which basically did nothing to prevent you from moving one of their phones to another carrier.
Can you hack into these phones? Of course you can. Many people buy expensive software and cables to "read" these secret codes. Some of the algorithms to generate these have also been cracked and can be found with a simple google search. Could I actually tell you how to get these codes illegally? You bet I can. I actually authored two such algorithms in the industry and could also tell you phone numbers to call where the system would give you the lock code for a particular carrier. But unfortunately this little problem with ethics prevents me from doing such a thing, even though I am not bound to any non-disclosure with these older companies. Call me old fashioned, but this industry is so small that if I were to burn my old companies I doubt I would be able to find work as a janitor in one of their offices.
You can send your phone off to these web site offerings on eBay and other places that promise to hack your phone for you and send it back ready to be activated on another carrier, or buy a phone for that company used there as well. The other option is you could just go in and get one at a steep discount and sign the two year contract. Most have annual policies to let you get another discounted handset every year, as long as you renew so they are basically giving you a discount to ensure you spend money with them.
Like I said, all wireless companies are about the same when you get down to the nitty gritty. One will have great coverage but no capacity, others might have better rates but no coverage or roaming. Bottom line is that by jumping ship you will be just going from one demon to another.