> 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/glossary.md).

# Glossary

There are many terms used in the M2M/ IoT/ Telecom world that can be confusing. Here’s an attempt to make sense of it.<br>

<table><thead><tr><th width="150"></th><th></th></tr></thead><tbody><tr><td><strong>Terms</strong></td><td><strong>Meaning</strong></td></tr><tr><td>2FF</td><td>Standard/ Traditional SIM (2nd form factor)</td></tr><tr><td>3-in-1 plug-in SIMs</td><td>SIMs that can be broken into Standard, Micro and Nano SIM form factors</td></tr><tr><td>3FF</td><td>Micro SIM (3rd form factor)</td></tr><tr><td>4FF</td><td>Nano SIM (4th form factor)</td></tr><tr><td>Automotive grade SIMs</td><td>Purpose built to comply with the automotive sectors’ tough quality management standards (such as PPAP, AEC-Q100) and with higher data retention span (15-17 years).</td></tr><tr><td>Embedded SIMs (eSIMs)</td><td>SIMs that can be embedded into devices, not meant for plug-in slots typically found in handsets. The machine Form Factor with the widely accepted Surface Mounted Device (SMD) form factor now being MFF2.</td></tr><tr><td>eUICC</td><td>While previously, a SIM would belong to a particular network operator, the eUICC allows the user to take control of the connectivity.</td></tr><tr><td>Industrial grade SIMs</td><td>Produced with higher resistance with an expanded temperature range of -40°C and +105°C. Other factors such as corrosion and impact on SIMs from vibrations were also improved.</td></tr><tr><td>MFF2</td><td>Standard embedded SIM Surface Mounted Device (SMD) (Machine form factor 2)</td></tr><tr><td>Standard grade SIMs</td><td>Operational within a temperature range of -25°C and +85°C</td></tr><tr><td>Subscription Management</td><td>Referred to also as Remote SIM Provisioning Platform, it is the counterpoint to interact with eUICC SIMs to manage profiles on a SIM.</td></tr></tbody></table>

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