VI.3 Numbering and addressing
VI.3.1 The structure of international and national numbers
To be able to set up a connection via switching telecommunications networks, the address of the destination is an indispensable requirement. In voice telephony networks, also if data is transmitted via these networks, this address is a number that is clearly identifiable in the worldwide network. Internationally, the structure of these numbers was defined by the ITU (Recommendation E.164). An international number consists of a maximum of 15 digits (without international prefix), the country code and the national significant number.
To indicate to the exchange that an international number is called, a so-called international prefix has to be dialled prior to the international number. In Austria, this international prefix is "00" and is often symbolised by a "+" before the international number (e.g. +43158058). The country code is allocated by the ITU and is "43" for Austria.
The structure of the national number is defined by the Numbering Ordinance (NVO).
Although the leading "0" (= national prefix) is not part of the area code, pursuant to NVO, it always has to be dialled prior to the respective area code, if the calling subscriber is located in Austria. The local network code, and thus the national prefix, need not be dialled in calls to geographic numbers in the same local network as the calling subscriber.
A national number consists of the regional or area code or the access code (see Table 16) and a number of a maximum of 9 digits or, with numbers in the public interest, an access of a maximum of 4 digits. Numbers of emergency services and special numbers consist only of their respective access codes.
| Table 16: National number ranges pursuant to the Numbering Ordinance (NVO) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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