ISO/IEC 14443-4:2018 Cards and security devices for personal identification - Contactless proximity objects - Part 4: Transmission protocol This document specifies a half-duplex block transmission protocol featuring the special needs of a contactless environment and defines the activation and deactivation sequence of the protocol. This document is intended to be used in conjunction with other parts of ISO/IEC 14443 and is applicable to proximity cards or objects of Type A and Type B. This product is a single user license only.Copying and/or networking is prohibited.By purchasing this product, you agree to abide by the AIM End User License Agreement.