<p>Telephone plug; TAE stands for "subscriber connection unit". The TAE plug has 6 poles, but usually only four poles are used. Coding lugs are attached along the length of the plug housing, which are located in the middle of the plug (TAE-N) or at the bottom edge (TAE-F) to prevent mismating. F-coded plugs are used for telephone sets, N-coded plugs for non-telephone sets, such as answering machines or fax machines. In multiple sockets, such as the TAE-NFN, the answering machine is typically plugged in on the left, the telephone in the middle and the fax machine on the right. F connections always have priority over N connections, which means that a telephone can still pick up a call even if the answering machine has already taken over the call. Telegärtner was significantly involved in the development of the TAE plug. </p>