DIN ETS 300139:1992-12 Integrated Services Digital Network (ISDN); Call Hold (HOLD) supplementary service; service description; english version ETS 300139:1992

标准编号：DIN ETS 300139:1992-12

英文标题：Integrated Services Digital Network (ISDN); Call Hold (HOLD) supplementary service; service description; english version ETS 300139:1992

德文标题：ISDN; Dienstmerkmal Halten; Dienstbeschreibung; Englische Fassung ETS 300139:1992

发布日期：1992-12

标准预览图