Subscriber Identity Module (SIM cards) are small data chips used to activate your phone. Much the same as a memory card, they store important information from your cell phone, such as text messages and contacts. Memory card storage disks (SD cards) are used in the same way as a memory stick or backup disk on your computer. In addition to storing data, memory cards can save external media files, whereas SIM cards cannot. While you cannot use your SD card as a means to activate your phone like a SIM card, you can use your SD card as a backup storage disk like a SIM card. Tips Warnings Writer Bio
