A radio terminal adjusts its data transmit power in response to received power control commands which specify a maximum transmit power level. The commands may be addressed to an individual radio terminal by means of a first address, or addressed to a group of radio terminals by means of a second address. In order that the data transmit power of an individual radio terminal is not disrupted by the commands addressed to a group, the radio terminal operates in two states. In the first state the radio terminal responds to commands comprising the first address and does not respond to commands comprising the second address. In the second state the radio terminal responds to commands comprising the second address. The radio terminal transfers from the first state to the second state in response to receiving a command comprising the first address and a predetermined value. On entering the second state the transmit power is set in accordance with the last-received command comprising the second address, thereby avoiding the need for transmission of a further command comprising the second address before transmission in the second state can proceed. Alternatively, or additionally, transmission rate may be controlled in the same manner.