03 🪪 SIM & eSIM

What does SIM stand for, and what is its basic function?

Subscriber Identity Module; it identifies your mobile device on the carrier's network.

What information is stored on a physical SIM card?

Carrier and subscriber information, a SIM ID, a phone number, cellular network details, and storage space for contacts and messages.

What happens if you physically move a SIM card from one phone to another?

Your phone number and associated network identity move to the new device, along with any contacts/messages stored on the SIM.

What is an eSIM, and how does it differ from a physical SIM?

An eSIM (embedded SIM) is a permanent electronic component built into the phone that can't be physically removed; it's transferred between devices using software rather than physically moving a card.

How can a user transfer or add an eSIM to a device?

Through phone settings, using options to transfer from an existing phone or by scanning a QR code.

What special consideration is needed when handling a physical SIM card?

Physical SIM cards are very small and often require a special tool to remove or insert.

Can a single phone support more than one SIM at a time?

Yes — some phones support multiple SIMs simultaneously, allowing multiple phone numbers or profiles on one device.