The SIM (Subscriber Identity Module) card is the small plastic card with an embedded electronic chip that gets inserted into the slot in the side /back/bottom of your mobile device. The SIM Card identifies provides you access to a specific wireless operator network (in Canada – Bell, TELUS, Rogers, Wind…). The SIM Card also stores the data that identifies you on the wireless network (the IMSI and MSISDN – your telephone number).
The body SIM Card is marked with an ICC-ID (Integrated Circuit Card -Identifier).
The SIM Card will only work with a phone that is locked to the same wireless network as the SIM Card provider, or with an “unlocked” mobile device. An “unlocked” phone will work on any wireless network, provided the phone supports the licensed RF spectrum that is used by your wireless operator.
SIM Cards come in different Sizes:
- Standard SIM
- Micro SIM
- Nano SIM
When you purchase a new phone and select a a plan your wireless service provider will program a SIM for you and install it in the phone for you. If at a later date you buy a new phone you are able to remove your SIM and install it in the new phone (assuming the device is locked to the same service provider or you purchased an “unlocked” phone). If the new phone requires a different sized SIM, you can purchase a new SIM from your service provider and have them move your account data to the new SIM card. You can also typically do this via your service providers online account portal.
You may have seen that local electronics stores and even grocery stores offer Cell Phone plans and as a result sell their own SIM Cards. These stores are acting as a MVNO (Mobile Virtual Network Operator). Basically they are selling Cell Phone plans that use another companies wireless network.
These SIM are required to identify you as being a MVNO subscriber and are charged usage fees based on the MVNO’s cell phone plans.