Subscriber Identity Module; a smart card installed or inserted into a mobile device containing all subscriber-related data. This facilitates a phone call from any valid mobile device since the subscriber data is used to complete the call rather than the telephone internal serial number. The SIM number is 15 digits.
You can locate the SIM by using the following steps:
1. Remove battery cover door and remove battery.
2. If SIM card phone, remove SIM card and read the number from white side of card.