a method of and a system for controlling low power radio frequency activity of terminals , including a method of selecting and activating a wireless terminal . a signal , including a transmission indication , is transmitted by a first terminal . a second terminal receives the signal a number of times and compares the received transmission indications with predetermined indication values . when the comparison shows that a predetermined number of satisfactory transmission indications have been received by the second terminal , the second terminal commences transmission . the transmission indication can be messages having tail portions with a preselected set of states .