DIN ETS 300512:1996-08 European digital cellular telecommunications system (Phase 2) - Procedure for call progress indications; English version ETS 300512:1996
1996DIN ETS 300512:1996-08 European digital cellular telecommunications system (Phase 2) - Procedure for call progress indications; English version ETS 300512:1996
1996DIN ETS 300512:1996 European digital cellular telecommunications system (Phase 2) - Procedure for call progress indications; English version ETS 300512:1996