ISO 14443 has two variants, Type A and Type B.
ISO 14443A was accepted by the ISO committee in 1997. It is the first ISO standard for 13.56 MHZ frequency contactless card which was developed by Mikron Austria and acquired by Phillips in 1996. Currently, ISO 14443A is the most widely used contactless standard in the world, mainly in transport applications.
The ISO14443A contactless card was originally intended to be a memory card only. However, microprocessor and cryptographic cards have been developed for Type A. The most common Type A cards are referred to as MIFARE cards.
ISO14443B contactless card was originally intended to be microprocessor version of Type A. Again, the memory and cryptographic options have been added for Type B thereby creating competition between Type A and Type B cards. The Type B cards are not as commonly deployed as Type A cards. ISO 14443B was approved by the ISO committee in 1998.
ISO 14443B has a number of advantages over ISO 14443A:
Unlike ISO14443A uses 100% modulation depth, it means that the reader stops emitting the field for defined periods of time. The modulation depth for ISO 14443B is only 10% which preserves the continuity of the clock.
No patents on communication coding.
Communication speeds of up to 847 KHz.
Adopted as a national standard by many countries, such as US, China, Japan, etc.
A third variant of the ISO 14443 standard, Type C, was developed by Sony, however, it was abandoned by the ISO/IEC committee and now is renamed as Felica.