The first generation of SIM cards, also known as 1FF or “credit card” sized SIM cards, were first introduced in 1991 by the European Telecommunications Standards Institute (ETSI). These SIM cards were used in the earliest mobile phones and were roughly the size of a credit card, measuring 85.60 mm x 53.98 mm x 0.76 mm.
1FF SIM cards were made of a rigid plastic material and had a small gold contact chip on one side. This chip contained important information such as the subscriber’s phone number and network security keys. The other side of the SIM card had a metal strip for connectivity.
These SIM cards were primarily used in GSM phones and were designed to be easily removable and transferable between devices. However, due to their large size, they were not practical for smaller mobile phones and were eventually replaced by smaller form factor SIM cards.
Despite their size, 1FF SIM cards were a major technological advancement at the time as they allowed for easy switching between mobile phones and networks. They also paved the way for the development of newer and smaller SIM card sizes such as the mini-SIM (2FF), micro-SIM (3FF), and nano-SIM (4FF).
Today, 1FF SIM cards are no longer used and have been replaced by smaller and more efficient SIM card sizes. However, they played a crucial role in the evolution of mobile phone technology and are a testament to the constant advancements in the telecommunications industry.