Provides specifications for the standardisation of the characteristics of the minimum required Network Control Facilities (NCFs) for Land Mobile Earth Stations (LMESs) with both transmit and receive capabilities operating on the 1z5/1z6 GHz and 11/12/14 GHz bands providing Low Bit Rate Data Communications (LBRDCs) in order to ensure that the network operator is able to suppress and enable transmission from the MESs.