This International Standard provides specifications of the access layer (OSI layers 1 and 2 and the related management functionality) of a communication interface (CI) named "CALM M5", operating in the 5 GHz microwave frequency range. CALM M5 CIs include communication modules (CMs) that are based on the wireless LAN technology standardized at IEEE. This International Standard specifies the additions to and deviations from IEEE 802.11, including the amendment [16] developed by IEEE Task Group p (TGp) required to make CALM M5 CIs compatible with the ITS station reference architecture based on the CALM concept specified in ISO 21217. Frequency allocations in regions other than North America are supported.