ISO/IEC 18000-4:2015 defines the air interface for radio frequency identification (RFID) devices operating in the 2,45 GHz Industrial, Scientific, and Medical (ISM) band used in item management applications. It provides a common technical specification for RFID devices that can be used by ISO committees developing RFID application standards. It is intended to allow for compatibility and to encourage inter-operability of products for the growing RFID market in the international marketplace. It defines the forward and return link parameters for technical attributes including, but not limited to, operating frequency, operating channel accuracy, occupied channel bandwidth, maximum equivalent isotropically radiated power (EIRP), spurious emissions, modulation, duty cycle, data coding, bit rate, bit rate accuracy, bit transmission order, and, where appropriate, operating channels, frequency hop rate, hop sequence, spreading sequence, and chip rate. It further defines the communications protocol used in the air interface.

ISO/IEC 18000-4:2015 contains the following three modes: Mode 1 is an interrogator talks first with passive tag; Mode 2 is a tag talks first with battery-assisted passive tag; Mode 3 is a globally available, ubiquitous network supporting, among others, the logistics and transportation industry; agnostic to any device, commercial or otherwise, requiring global availability.

The detailed technical differences between the modes are shown in the parameter tables.