Cellular devices have many numbers associated with them, especially with respect to the SIM cards. Here’s a short list to keep them straight:
IMEI stands for International Mobile Station Equipment Identity and is used to identify 3GPP (also known as GSM (AT&T, TMobile, UMTS and LTE devices/networks) and iDEN mobile phones, as well as some satellite phones. It is usually found printed inside the battery compartment of the phone and often on the box the phone came in (think iPhone), but can also be displayed on-screen on most phones by entering *#06# on the dial pad, or alongside other system information in the settings menu on smartphone operating systems.
The IMEI is part of the phone, not the SIM card so swapping SIM cards won’t change the IMEI. (Kind of like a serial number)
ICCID stands for Integrated Circuit Card ID. This is the identifier of the actual SIM card itself – i.e. an identifier for the SIM chip. It is possible to change the information contained on a SIM (including the IMSI), but the identify of the SIM itself remains the same.
This allows you to swap SIM cards between phones and makes GSM style phones more convenient to use when you break your phone and want to swap it with a spare.
SIM stands for subscriber identification module and is basically the serial number of the card that you put in your GSM phone.
SIM cards come in many sizes, currently they are:
|SIM card||Introduced||Standard reference||Length (mm)||Width (mm)||Thickness (mm)||Volume (mm3)|
|Full-size (1FF)||1991||ISO/IEC 7810:2003, ID-1||85.60||53.98||0.76||3511.72|
|Mini-SIM (2FF)||1996||ISO/IEC 7810:2003, ID-000||25.00||15.00||0.76||285.00|
|Micro-SIM (3FF)||2003||ETSI TS 102 221 V9.0.0, Mini-UICC||15.00||12.00||0.76||136.80|
|Nano-SIM (4FF)||early 2012||ETSI TS 102 221 V11.0.0||12.30||8.80||0.67||72.52|
|Embedded-SIM||JEDEC Design Guide 4.8, SON-8||6.00||5.00||<1.0|
UICC is the physical card most users refer to as a SIM. It stands for Universal Integrated Circuit Card. The SIM is a circuit component of this card.
Hope that helps. It’s shocking how the carrier customer service reps have no idea what any of this is an always ask you to read the longest number possible when they know full well the don’t need it….