Originally, the first digits following the area code would indicate a smaller area within these area codes or the type of the subscriber line (analogue or ISDN). However, this is no longer true as subscribers can keep their numbers when moving within an area code or when switching from analogue to ISDN. Further, new carriers assign numbers from different blocks.
Plain Old Telephone Service
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Plain Old Telephone Service - Germany - Europe Phones
Plain Old Telephone Service Europe
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