Are NFC/HF cards interchangeable?

Question

I want to specify the equipment for a proposal of a system using RFID for several features. It might be expanded in the future to include transactions so I am trying to find the right technology to use.

The plan is to use passive cards.

HF/NFC cards/Readers operate in the same frequency but can they be used interchangeably, as in an HF reader reads/writes NFC cards and the opposite?

and what is the different between them on architecture level?

Answer 1

NFC is collection of different standards: ISO 14443-4 (Type A and Type B proximity cards), JIS 6319-4 (FeliCa) and ISO 18092 (NFC peer-to-peer, which uses parts of ISO 14443 and JIS 6319-4). Quite a few NFC devices also implement ISO 15693 (vicinity cards). These standards all use a frequency of 13.56MHz.

Besides that, quite a few legacy systems are common still: MIFARE, Calypso, Picopass, CryptoRF, Legic, etc. These are often compliant to (parts of) ISO 14443-3.

The NFC Forum attempts to unify various aspects of these standards and their usage and define common standards on top of them to enable the interoperability of different implementations, see e.g. http://www.nfc-forum.org/specs/spec_list/.

There exist card readers that can handle all of these protocols but more commonly a card reader only supports a subset. For example, only ISO 14443 or only ISO 15693, or the combination ISO 14443 and FeliCa, or (worse) only ISO 14443-3 or only ISO 14443-4 Type A. Support for a legacy system you usually only find in (chips for) card readers from a particular manufacturer, e.g. NXP Semiconductors for MIFARE.

Another complication in practice is that when the hardware can support certain cards it does not necessarily mean that the accompanying software (driver, support library) also can handle them.