TAE (Telekommunikations-Anschluss-Einheit) is the German standard for telephone plugs and sockets.
The standard covers two TAE types: F ("Fernsprechgerät": for telephones) and N ("Nebengerät": for other devices such as answering machines and modems).
||Color of the wire
||Exchange line a
||Exchange line b
||Line for external bell (obsolete since mid-1990s)
||Line for ground connection, used to request an external connection in very old telephone installations
||Line a, looped through the telecommunication device
||Line b, looped through the telecommunication device