duplex 2 way radio Full-duplex, clear sound CE/ ... within 6 seconds, red light twinkles three times and machine goes to synchronous mode, synchronization ok ... 6 seconds, red light twinkles one time and exits from Configure Code status then return to ... 2) Full-duplex hands-free voice call, voice loud and clear 3) Improved frequency-hopping technology, super error-correcting and anti-jamming capability 4 ...