| Some time ago, I was in charge of developing a | | | | operators, enabling the user to successfully use |
| business concern on the beautiful island of Sri | | | | their phone in many parts of the world. One of |
| Lanka while based in the United States. At one | | | | the key differences with GSM is that the phone |
| point, I needed to send an employee there to set | | | | itself is not directly linked to you. Rather, the |
| up the quality control program. This employee did | | | | removable "SIM" (Subscriber Information Module) |
| not have a GSM cell phone so I lent him mine to | | | | chip is encoded with a unique serial number which |
| use "in case of emergency only". The employee | | | | is what now identifies you to the wireless |
| spent time each night chatting with family on the | | | | provider. |
| cell phone and came back with a $3,000 phone bill | | | | Having your info embedded into a removable SIM |
| in two short weeks. | | | | chip rather than into your cell phone is what |
| If you have a US GSM cell phone and service | | | | makes this all so interesting. If you place your SIM |
| account, you may find that it will cost you | | | | chip into a compatible cell phone, you can use that |
| something in the range of $3 per minute to use | | | | phone as your own because the service provider |
| your phone overseas due to international roaming. | | | | will recognize the SIM chip inside of it as yours. |
| As an example, on one trip to Hamburg, I had | | | | Conversely, you can buy compatible SIM chips |
| lost my party at a very large exposition. I used | | | | from the country you are about to visit and use |
| my cell phone to call them and found out that | | | | them in your phone. This is what allows you to |
| instead of it being a local call, it went to the US | | | | avoid the ugly international roaming charges |
| and back via their networks thus charging me for | | | | mentioned above. |
| two international calls! | | | | Before you can do this, however, you will most |
| A little while later I was on a plane to Sri Lanka. | | | | likely need to "Unlock" your cell phone. Most |
| As we were about to land, the gentleman next to | | | | wireless service providers "lock" their cell phones |
| me took out a small bag and dumped the | | | | which means that they program them to only |
| contents into his palm. They were SIM chips. I | | | | work with SIM chips issued by their company. |
| asked him what this was all about and he told me | | | | Unlocking a cell phone is basically reversing this |
| he was looking for his chip for Sri Lanka. He | | | | programming. The process is very easy and quick. |
| informed me that the chip enabled him to make | | | | There are many service providers online that |
| calls in and from Sri Lanka without incurring the | | | | specialize in mobile unlocking. Once the cell phone is |
| extremely high roaming charges my friend above | | | | unlocked, it is permanently unlocked. |
| met with. He traveled throughout Europe and Asia | | | | Now I wanted a SIM chip that would work in the |
| and had chips for each major locale. | | | | country I was headed too, again, Sri Lanka. I was |
| I was intrigued by this idea and did some research | | | | told that the best way was to find a cell phone |
| on what it took to use these local chips in my cell | | | | store there in Colombo but this sounded difficult |
| phone. Here is what I found: | | | | as my schedule would be very busy. While |
| Your basic cell phone service provider places a | | | | searching for an alternative, I was directed to as |
| unique serial number into your cell phone. This | | | | a source of chips via the internet. I found that I |
| unique number is called an "ESN" and it is used by | | | | could buy a chip from Sri Lanka with pre-paid |
| the service provider to identify who you are. The | | | | minutes on it. They did also offer a great variety |
| service provider uses this number to know where | | | | of SIM chips from most major destinations |
| to send phone calls too when someone dials your | | | | around the world. The process was quick and |
| number. | | | | painless and I found the cost to be very |
| A GSM phone is a little different animal. "GSM" | | | | reasonable ($79 vs. $3,000!). The only drawback |
| (Global System for Mobile Communications) is a | | | | to the system was that this did give me a new |
| type of digital mobile phone service. GSM is the | | | | phone number which I had to pass out to family |
| most common standard for cell phones in the | | | | and business associates prior to departure. |
| world. GSM service is common in over 210 | | | | The trip went well as I was able to coordinate |
| countries around the world with over 1.5 billion | | | | activities with local vendors and business |
| users. The popularity of GSM makes international | | | | associates without feeling like I had to hang up |
| roaming very common between cell phone | | | | the phone after two sentences. |