You are the full name of the SIM card we have on our mobile, the Subscriber Identification Module. It is an integrated circuit that operates the card operating system (COS).
It securely stores International Mobile Customer Identification (IMSI) numbers and related keys. Mobile telephony devices (mobile devices) use such numbers and keys to identify and authenticate customers.
The SIM card used in mobile phones has a width of 25 mm, a length of 15 mm, and a thickness of 0.76 mm. If you look closely at the SIM card, a corner is cut.
The main purpose of cutting one corner of all SIM cards is to correctly connect the SIM card to the PIN contact. The PIN number 1 of the SIM card has to be linked to the corresponding PIN of the mobile phone.
The cut part serves as an instruction to place the SIM card in a suitable place on the mobile phone. If a corner was not cut on the SIM card, it would be difficult to place it correctly on the mobile phone.
Similarly, there was a danger of keeping the SIM card upside down in the mobile phone. That is why one corner of the SIM card is cut off.
If you look at the SIM card tray of a mobile phone, there is also a signal to insert the SIM card correctly. This means that the appropriate location in the SIM tray is based on the corner of the SIM card.