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