SIM File-System Reference
An interactive, linkable reference tree of the UICC / USIM / SIM file system — FIDs, structure, access conditions, the SELECT APDU to reach each file, and field decoders for well-known EFs.
EF_ICCID
2FE2transparentIntegrated Circuit Card Identifier, stored as swapped-nibble BCD (ITU-T E.118). Readable without a PIN.
- Typical size
- 10 bytes
- Structure
- transparent
- Read
- ALW
- Update
- NEVER
- Spec
- ETSI TS 102 221 §13.2
- SELECT APDU
- 00A40004022FE2
Navigating the tree
Every path starts at the Master File (3F00). Click a file to see its FID, structure, typical
size, access conditions, spec reference and the exact SELECT APDU chain — then paste raw content into the
per-EF decoder where one is available (ICCID, EF_IMSI, EF_SPN, EF_AD, service tables).
Classic SIM vs USIM
The same logical file can live at a different path and use different coding on a classic GSM SIM
(DF_GSM under the MF, class byte A0) versus a USIM (ADF_USIM selected by
AID, class byte 00). Where that divergence matters, the file's notes call it out.
FAQ
What are MF, DF and EF?
The UICC file system is a tree. The Master File (MF, 3F00) is the root. Dedicated Files (DFs) group related files — DF_TELECOM (7F10), DF_GSM (7F20) — and Application Dedicated Files (ADFs) hold an application like ADF_USIM. Elementary Files (EFs) hold the actual data, structured as transparent, linear-fixed or cyclic.
What do the access conditions mean?
Each file has READ and UPDATE conditions: ALW (always), PIN (CHV1), PIN2, ADM (administrative key held by the issuer) or NEVER. ADM-protected files are not readable on a production card without the operator's ADM key — the same caveat pySim documents.
How is a service table numbered?
Service tables (EF_UST, EF_EST, EF_SST) are bit maps with 1-based service numbers: service n is bit ((n-1) mod 8) of byte floor((n-1)/8). Paste a table into the file's decoder here to list the enabled services.
Related tools
Need this at production scale?
Senior SIM/USIM/OTA consulting, applet development and operator advisory — EN/PT.