Dual-Interface Module

What Is a Dual-Interface Module?

A dual-interface moduledual-interface moduleHardwareSingle chip supporting both contact and contactless interfaces.Click to view → is a smart card chip that supports both the ISO 7816 contact interface and the ISO 14443 contactless interface on a single silicon die. This allows one card to operate in contact mode when inserted into a reader and in contactless mode when tapped against an NFC terminal, using the same secure element, the same application data, and the same cryptographic keys.

Dual-interface technology is the standard for modern EMV payment cards, national eID cards, and multi-application corporate badges that must support both legacy contact readers and modern contactless infrastructure.

Architecture

The dual-interface module integrates several components on a single chip:

• Contact interface -- eight contact pads (C1-C8) per ISO 7816ISO 7816StandardPrimary standard for contact smart cards.Click to view →-2 for VCC, GND, CLK, RST, I/O, and optional SWPSWPProtocolSingle-wire link between SIMSIMApplicationSmart card for mobile network authentication.Click to view → and NFC controller.Click to view → (C6).
• Contactless interface -- an RF transceiver connected to an antenna coil embedded in the card body, operating at 13.56 MHz.
• Shared secure elementsecure elementSecurityTamper-resistant hardware for secure operations.Click to view → -- the CPU, EEPROM or flash memory, and crypto coprocessor are shared between both interfaces.
• Interface arbiter -- logic that prevents simultaneous activation of both interfaces and manages power switching between contact (external VCC) and contactless (RF-harvested) power sources.

How Interface Switching Works

The chip automatically detects which interface is active:

The contactless interface is automatically disabled when the contact interface is powered, preventing relay attacks and ensuring deterministic behavior during transactions.

Manufacturing Considerations

Building dual-interface cards requires connecting the chip module to an antenna coil during chip embedding. The antenna is typically etched or wound into the card bodycard bodyHardwarePlastic substrate forming the card physical structure.Click to view → layers before lamination, and connection to the module is made through laser welding or conductive adhesive at two bonding points. This manufacturing step is more complex than single- interface cards and requires precise alignment during the card body assembly process.

Cards like the EMV Dual-Interface and ePassport rely on dual-interface modules to serve both chip-and-PIN terminals and contactless tap-to-pay readers.