The UICC with the SIM or USIM application plays an important role in mobile telephony as it is the secure element identifying a subscriber in the network and allowing MNOs to bill the respective account.
Hence it is crucial to have standardised features e.g. placing phone calls or sending SMS working throughout the global network with all available handsets and (U)SIM cards resp.
Developing globally applicable standards for communication technologies is the task of standardisation bodies such as ETSI (European Telecommunications Standards Institute, 3GPP (Third Generation Partnership Project) and 3GPP2 (Third Generation Partnership Project 2).
Important test specifications for the (U)SIM interface are: Before mobile network operators select new handset types to be offered to their customers, they want to be sure the new handset will support all features and work in combination with new and existing UICCs.
They select relevant test cases and define an independent certification programme for handset type approval.