The SIM card has a few gold-colored parts. These are contacts. They connect the SIM card to the phone's insides. When you turn your phone on, it reads the data from the card. It looks for the IMSI number. This number is sent to the mobile network. The network checks the number. If everything is correct, the network gives your phone a signal. Therefore, you can make calls and use the i... b2creviews.club