▁A ▁cogn itive ▁radio ▁system ▁still ▁being ▁sold ▁and ▁in ▁use ▁as ▁of ▁ 2 0 1 1 . ▁ ▁Walk ie ▁talk ies ▁M oto T alk ▁or ▁with ▁Next el , ▁Direct T alk , ▁uses ▁the ▁ 9 0 0   M Hz ▁Part ▁ 1 5 ▁band . ▁ ▁It ▁uses ▁F H SS ▁and ▁emp lo ys ▁ 1 0 ▁" ch annels " ▁and ▁ 1 5 ▁" priv acy ▁codes ". ▁ ▁This ▁is ▁available ▁as ▁a ▁feature ▁on ▁several ▁of ▁the ▁walk ie - t alk ie ▁ph ones , ▁for ▁" off ▁network " ▁simple x ▁communic ations . ▁ ▁Motor ola ▁makes ▁a ▁line ▁of ▁walk ie - t alk ies ▁( the ▁D TR ▁family ) ▁which ▁are ▁F H SS ▁digital ▁units . ▁ ▁They ▁are ▁very ▁similar ▁to ▁the ▁Direct T alk - cap able ▁i D EN ▁cell ph ones , ▁even ▁sharing ▁some ▁access ory ▁items , ▁but ▁they ▁can ▁not ▁inter oper ate ▁with ▁Direct T alk ▁units . ▁ ▁Tr is quare ▁makes ▁a ▁line ▁of ▁walk ie - t alk ies ▁( the ▁e X tre me ▁Radio ▁Service ▁family ) ▁that ▁are ▁also ▁license ▁free ▁F H SS ▁units , ▁operating ▁in ▁the ▁ 9 0 0   M Hz ▁band . ▁ ▁They ▁are ▁similar ▁to ▁Direct T alk ▁but ▁not ▁compatible . ▁ ▁Current ▁amateur ▁uses ▁Today , ▁the ▁ 3 3 ▁cent imeter ▁band ▁is ▁rapidly ▁becoming ▁popular ▁with ▁many ▁U