Both the devices, Apple iPhone 4S and iPhone 4 uses a micro SIM which is just 15 mm × 12 mm in size and the same SIM tray. While the standard Mini SIM used with other mobile phones come in 25 mm × 15 mm in size. So, iPhone users must replace their existing SIM to micro SIM with the service network operators. Also, there are some mobile phone store keepers will trim the regular SIM to the micro-SIM size. However, it is always advisable to use the micro-SIM provided by network operators. Now, we shall understand how insert and replace SIM card in Apple iPhone 4S and Apple iPhone 4 in simple steps.
Steps to Insert a SIM card: