▁mode ' ▁where by ▁they ▁share ▁channels ▁directly ▁( walk ie - t alk ie ▁mode ). ▁ ▁Gate way ▁mode ▁- ▁where ▁a ▁single ▁mobile ▁with ▁connection ▁to ▁the ▁network ▁can ▁act ▁as ▁a ▁relay ▁for ▁other ▁nearby ▁mob iles ▁that ▁are ▁out ▁of ▁range ▁of ▁the ▁infrastr ucture . ▁A ▁dedicated ▁trans ponder ▁system ▁isn ' t ▁required ▁in ▁order ▁to ▁achieve ▁this ▁functionality , ▁unlike ▁with ▁analog ue ▁radio ▁systems . ▁ ▁T ET RA ▁also ▁provides ▁a ▁point - to - point ▁function ▁that ▁traditional ▁analog ue ▁emer gency ▁services ▁radio ▁systems ▁did ▁not ▁provide . ▁This ▁enables ▁users ▁to ▁have ▁a ▁one - to - one ▁tr unk ed ▁' radio ' ▁link ▁between ▁sets ▁without ▁the ▁need ▁for ▁the ▁direct ▁invol vement ▁of ▁a ▁control ▁room ▁operator / dispatch er . ▁ ▁Un like ▁cell ular ▁techn ologies , ▁which ▁connect ▁one ▁subscri ber ▁to ▁one ▁other ▁subscri ber ▁( one - to - one ), ▁T ET RA ▁is ▁built ▁to ▁do ▁one - to - one , ▁one - to - many ▁and ▁many - to - many . ▁These ▁oper ational ▁modes ▁are ▁directly ▁relevant ▁to ▁the ▁public ▁safety ▁and ▁professional ▁users . ▁ ▁Security ▁T ET RA ▁supports ▁terminal ▁registration , ▁authentication , ▁air - interface ▁encryption ▁and ▁end - to - end ▁encryption . ▁ ▁Rap id ▁deployment ▁( transport able ) ▁network ▁solutions ▁are ▁available ▁for ▁dis aster ▁relief ▁and ▁temporary ▁capacity ▁provision . ▁ ▁Network ▁solutions ▁are ▁available ▁in ▁both