number range
The numbering space is a numbering hierarchy standardized by the International Telecommunication Union( ITU) in Recommendation E.164 for telephone numbers and service numbers in the public telephone network, ISDN, and the mobile network. In Germany, the numbering space is administered by the regulatory authority RegTP.
The telephone numbers, service numbers and services are identified by prefixes and service codes. For example, the prefix "0" is used in mobile networks, followed by the service codes 15, 16, and 17. Shared-cost services(SCD) occupy the number space 0180, online services 0190 (switched off in mid-2006), and premium rate services( PRS) 0900.
With 0700 numbers, the RegTP has released numbers for the German telephone network that are not tied to a specific location and can always be retained by the user. The advantage of these 0700 numbers is that, regardless of whether they are used for private or commercial purposes, the number can be retained in the event of relocation and can be used as a so-called vanity number inconjunction with the name or company name. Example: 0700-FIRMIERUNG, instead of 0700-33451267.
Internationally, there is a numbering space for Europe in the form of the European Telecommunications Numbering Space( ETNS).