The Smartphonematters SIM Card Guide

I wrote a new Guide for SIM card and created my first video for smartphonematters. Check it out.


In this video, I explain SIM cards. You’ll learn about:

  • What is a SIM card, and why you need one
  • Some advantages to SIM cards
  • Choose the correct SIM for your network
  • Learn about the different SIM card sizes
  • See how to install a SIM in three different phone


SIM Guide Transcript

Your phone may need a SIM to work with your cellular telephone company. A SIM is a small card you insert into your phone. Your phone uses the SIM recognize and connect to the company’s wireless network. The cellular telephone company uses it to recognize which phone on the network belongs to you.

There are a couple advantages to SIM cards. Your cellular telephone account is associated with the SIM, not your phone. You can move your SIM from one one phone to another. For example, if you buy a new phone or replace your old phone you can just move the SIM from the old phone to the new phone and use it without calling the cellular telephone company.  Or maybe you want to try out a different phone. Suppose you had an iPhone, but you wanted to try a Windows phone. Move the SIM card from the iPhone to the Windows phone.

You can also use more than one cellular account, or SIM cards in your phone. Suppose you were travelling abroad to study for a semester in Europe. You can set up an account with a local cellular telephone company, get a local number, and use that account during your extended stay. You’ll save big money because you won’t need to pay your US cellular telephone company the very expensive data roaming fees.

SIM Card

Your SIM card is a small plastic card with metal contacts on one side. The SIM card has some electronic circuits inside. The contacts on the SIM align with contacts inside the phone, so that your phone can read the SIM.

Choose The Correct SIM card for Cellular Telephone Company

Mae sure you buy the correct SIM card for your cellular telephone company. If you want to use AT&T, get an AT&T SIM. If you want to use T-Mobile, get a T-Mobile SIM. If you want to use Straight Talk Wireless, get a Straight Talk SIM. You cannot use the SIM card from one company  if your have your account on another company. For example, you can’t sign up for T-Mobile using a SIM from AT&T.

Get The Correct Size SIM For Your Phone

SIM cards come in three different sizes. They are standard, micro, and nano. Choose the correct size SIM for you phone. All SIMs come attached to a credit card sized piece of plastic. The SIM is perforated on the card and you need to remove the SIM from the card.


The plastic card your SIM comes on might not be labeled with the SIM’s size.  Look carefully at the SIM packaging to see what size the SIM is. To figure out the SIM size, orient the SIM with the metal contacts facing you and the cut corner located on the bottom right.  A standard SIM has a large amount of plastic on the right side of the contacts. The Micro SIM has much less plastic arounf the sides of the contacts. It as more plastic along the bottom edge. Finally, the nano SIM has almost no plastic around the edges at all.

Inserting Your SIM Into Your Phone

To install the SIM in your phone you may need a SIM ejection tool. A SIM ejection tool is simple a peice of metal with a small pin on one end.  Check the box your phone came for the SIM ejection tool. If your phone didn’t come with one, you can buy some on Amazon or eBay. I paid $1.50 for six. You can also use a paper clip by straightening one end. Using the tool is better but you can get by with the paper clip.

To insert the SIM in your phone, find the SIM tray, use the SIM ejection tool to remove the tray. Remove the old SIM if present, and insert your new SIM in the tray. Make sure to orient the SIM in the tray correctly. Match the cut corner on your SIM with the cut corner on the SIM tray. Once the SIM is in the tray, insert the tray back into the phone.  Make sure you orient the SIM tray correctly. On many phones you can line up the ejection hole on the phone with the ejection hole on the phone.  When you insert the tray, make sure it is going in smoothly. You may feel a little pressure and hear a click when it snaps in. If the SIM tray isn’t going in correctly, make sure the SIM is seated in the tray correctly.

In the video, I demonstrate inserting the standard size SIM into an iPhone 3G. I also show how to instal a micro SIM in a Windows Phone, the Nokia Lumia 920. Finally, I show how to install the nano SIM in an iPhone 5s.


  1. sherry jones | | Reply

    Ok. Thank You very much for all your help.

  2. sherry jones | | Reply

    Yes. I see the E. So do I just purchase another sims card with tmobile?

    • Bob Thompson | | Reply

      If you get a straight talk tmobile sim, you can transfer your service to that card and try it. I can’t say it will work better. If you bought a byop kit at Walmart, it had four sims in it and you have the tmobile sim you would need. Otherwise you’ll have to order one from straight talk.

      It depends on the phone and the tmobile network in your area. One think you could do is go to both an att store and a tmobile store when they aren’t busy and tell them you are thinking of switching to their prepaid service enhanced you current service runs out. Ask to try a sim in your phone to see how well data works.

  3. sherry jones | | Reply

    So this means there is no help for my phone?

    • Bob Thompson | | Reply

      Hi Sherry,
      I found this listing on eBay
      I am assuming this us your phone.
      It says it supports 3G (WCMDA) on the 850 and 2100 radio frequencies

      ATT uses 850 for 3G service is some areas. TMobile uses 2100 for 3G in some areas. Do you see a 2G or E in your status bar when you use data connection? I suspect this may also be why this phone is so inexpensive. You might have better luck using the ST tmobile SIM. Check you settings to see if there in an option to turn 3G on and off. Make sure its on.


  4. sherry jones | | Reply

    Hello. My phone model is a F7102. I bought it new. It never been on another system.

    • Bob Thompson | | Reply

      I looked at your phone’s specs. It to me like your phone supports limited radio frequencies for 3G service on the AT&T network.

  5. sherry jones | | Reply

    I have 2 questions. One is I have an android note2 unlocked with net 10 on art network. My sim card is much smaller then the holder it fits in. Could this cause my phone not to pick up cause it is very slow using the internet. Also I have tried several things to get/receive MMS. I really need help

    • Bob Thompson | | Reply

      Hi sherry,
      This means you have a nano SIM or micro SIM and your phone uses a micro SIM or standard size SIM. You have two choices. Transfer you net10 service to a new SIM or use a SIM card adapter. SIM card adapters are the subject of my next video!

      This wouldnt cause your phone to be slow. I suspect you are getting a 2G data connection. What model number is your Note 2 and what network was it previously on?

      You can learn how to set up MMS here
      Help Setting up Straight Talk Data and MMS on the Samsung Galaxy Note 2 Running Android 4.1

      Give it a try

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