 DAB uses a wide-bandwidth broadcast technology and typically spectra have been allocated for it in Band III (174–240 MHz) and L band (1.452–1.492 GHz), although the scheme allows for operation between 30 and 300 MHz.The US military has reserved L-Band in the USA only, blocking its use for other purposes in America, and the United States has reached an agreement with Canada to restrict L-Band DAB to terrestrial broadcast to avoid interference.DAB historically had a number of country-specific transmission modes (I, II, III and IV).