Hello, the number you have dialed is offline, please dial again later.

If it hasn't been used for a long time, it will say, "Hello, the number you have dialed is not in service".

SIM card is the abbreviation of (Subscriber Identification Module?), also known as subscriber identification card, ? Smart card, GSM digital mobile phone must be loaded with this card in order to use. It stores the digital cell phone customer information, encrypted keys and the user's phonebook on a computer chip, which can be used to identify the customer's identity in the GSM network. The card can be used to identify the customer's identity and encrypt the customer's voice information during the call.