> For the complete documentation index, see [llms.txt](https://docs.connectedyou.io/knowledge-base/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.connectedyou.io/knowledge-base/connectedyou-platform/user-guide/euicc-centre.md).

# eUICC Centre

The ConnectedYou SIM is built using standard & industry approved eUICC functionality to manage Connectivity Providers on the SIM with GSMA endorsed security guidelines. This GSMA eco-system of Subscription Management, called “Remote SIM Provisioning” system is used to manage these eUICCs. Refer to [here](https://docs.connectedyou.io/knowledge-base/v/sim-esims/connectedyou-sim/euicc-functionality) for more details. 

eUICCs allows the user to retain control of the physical SIM via the ability to switch the Connectivity Provider at will.

There are 2 types of eUICCs enabled via the ConnectedYou platform: Cloud eUICCs and SAS eUICCs which correspond to the RSP platforms they communciate with (Cloud & SAS).

### Cloud RSP platform

### SAS RSP platform