SIM cards are small cards that contain the personal information that's stored on your cell phone. SIM stands for Subscriber Identity Module, and all phones on the Global System for Mobile Communications (GSM) network use these cards. SIM cards make transferring phones much easier, as you simply remove your card and slide it into the new phone, and all of your contacts and other personal data get transferred right over.
The SIM card also helps your service provider connect your phone to their network. Remove the battery and place it aside. You will see the SIM card resting beneath where the battery was. The SIM card looks like a small card with a gold chip on the front. Avoid touching the gold chip.
Take the SIM card out of the slot, gently removing any clips that are holing it in place. Turn the card over, and write down the number on the back. This is your SIM card number. Put the SIM card back in its slot gently, and secure it with the metal clips you removed while taking it out. Replace the battery, and slide the battery cover back in place. You can now power up your cell phone again.
Re: check sim card Elector Dec 21, 2014 8:18 AM ( in response to jaezs ) Bring the phone to a corporate store not a reseller. Using IMEI serial number you will be able to know the iPhone is unlocked with the Sim card. Make use of the IMEI checker feature to achieve this task optimally. Check if iPhone is unlocked via settings. You can make use of ‘Settings’ option to know whether the iPhone is unlocked with the Sim Card or not.