DIN ETS 300503:2001-04 Digital cellular telecommunications system (Phase 2) - General on supplementary services (Endorsement of the English version ETS 300503:1996-05 as German standard) / Note: Endorsement notice
2001DIN ETS 300503:2001-04 Digital cellular telecommunications system (Phase 2) - General on supplementary services (Endorsement of the English version ETS 300503:1996-05 as German standard) / Note: Endorsement notice
2001DIN ETS 300503:2001 Digital cellular telecommunications system (Phase 2) - General on supplementary services (Endorsement of the English version ETS 300503:1996-05 as German standard)