▁reliable ▁circuit - switch ed ▁( tele phone ▁like ) ▁architect ures ▁and ▁flat , ▁IP ▁architect ures ▁with ▁soft ▁( software ) ▁switch es . ▁ ▁Further ▁information ▁is ▁available ▁from ▁the ▁T ET RA ▁Association ▁( former ly ▁T ET RA ▁Mo U ) ▁and ▁the ▁standards ▁can ▁be ▁downloaded ▁for ▁free ▁from ▁E T SI . ▁ ▁Dis adv antages ▁ ▁Its ▁main ▁dis adv antages ▁are : ▁▁ ▁Re qu ires ▁a ▁linear ▁ampl ifier ▁to ▁meet ▁the ▁string ent ▁R F ▁specific ations ▁that ▁allow ▁it ▁to ▁exist ▁alongside ▁other ▁radio ▁services . ▁ ▁Data ▁transfer ▁is ▁slow ▁by ▁modern ▁standards . ▁Up ▁to ▁ 7 . 2   k bit / s ▁per ▁times lot , ▁in ▁the ▁case ▁of ▁point - to - point ▁connections , ▁and ▁ 3 . 5   k bit / s ▁per ▁times lot ▁in ▁case ▁of ▁IP ▁enc aps ulation . ▁Both ▁options ▁permit ▁the ▁use ▁of ▁between ▁one ▁and ▁four ▁times l ots . ▁D ifferent ▁implementations ▁include ▁one ▁of ▁the ▁previous ▁connect ivity ▁capabilities , ▁both , ▁or ▁none , ▁and ▁one ▁times lot ▁or ▁more . ▁These ▁rates ▁are ▁ost ens ibly ▁faster ▁than ▁the ▁compet ing ▁techn ologies ▁D MR , ▁d PM R , ▁and ▁P 2 5 ▁are ▁capable ▁of . ▁ ▁Lat est ▁version ▁of ▁standard ▁supports ▁ 1 1 5 . 2   k bit / s ▁in ▁ 2 5   k Hz ▁or ▁up ▁to ▁ 6 9 1 .