... E1; 3)With SIP protocol; 4)Signaling support: SS7, ISDN PRI, R2, Q.SIG, V5.2; Brief IntroductionNC-AD300E PBX is ... * E1 Signaling Support: SS7, ISDN-PRI, Q.SIG, V5.2.* T1 Signaling Support:SS7,ISDN-PRI* SIP Protocol * CodecsG.711-pcma, G.711 ...