IEC IEC 62820-3-1 Edition 1.02017-12 INTERNATIONAL STANDARD NORME INTERNATIONALE Building intercom systems - Part 3-1: Application guidelines - General Systemes d'interphone de batiment- Partie 3-1: Lignes directrices d'application - Generalites IEC IEC 62820-3-1 Edition 1.02017-12 INTERNATIONAL STANDARD NORME INTERNATIONALE Building intercom systems - Part 3-1: Application guidelines - General Systemes d'interphone de batiment- Partie 3-1: Lignes directrices d'application - Generalites IEC IEC 62820-3-1 Edition 1.02017-12 INTERNATIONAL STANDARD NORME INTERNATIONALE Building intercom systems - Part 3-1: Application guidelines - General Systemes d'interphone de batiment- Partie 3-1: Lignes directrices d'application - Generalites