SIM Card Pinout
ISO/IEC 7816 smart-card contact layout used by mini/micro/nano SIMs.
Overview
A SIM is an ISO/IEC 7816 smart card. Regardless of plastic form factor (mini/micro/nano), the electrical interface is the same contacts C1-C8, of which typically six are used.
Communication is half-duplex serial over a single I/O line (C7), clocked by the host (C3) and reset via C2, with power on C1 and ground on C5. C4/C8 now carry USB D+/D- on some cards; C6 (VPP) is largely obsolete.
Pinout
| Pin | Name | Function | Description |
|---|---|---|---|
| C1 | VCC | POWER | Supply voltage (1.8 / 3 / 5 V) |
| C2 | RST | SIGNAL | Reset signal to the card |
| C3 | CLK | CLK | Clock supplied by the host |
| C4 | AUX1 / USB D+ | SIGNAL | Reserved; USB D+ on USB-capable cards |
| C5 | GND | GND | Ground / reference |
| C6 | VPP / SWP | SIGNAL | Programming voltage (legacy) / single-wire protocol |
| C7 | I/O | DATA | Half-duplex serial data in/out |
| C8 | AUX2 / USB D- | SIGNAL | Reserved; USB D- on USB-capable cards |
Notes
- Contacts are designated C1-C8 per ISO/IEC 7816-2.
- Many SIMs omit C4 and C8 when USB/SWP is not implemented.
Reference: ISO/IEC 7816-2 smart-card contact assignment· verified 2026-06-27