Just as in the traditional telephone network, users of Voice over IP (VoIP) receive a phone number from the provider which they can use to get calls. However, there are several problems that are connected with the technical features of Voice over IP. One problem is that when using VoIP it is impossible to determine the number. This is important, for example, for calls to emergency numbers.
There has been a lot of thinking on how to resolve the issue of phone numbers and what impact it will have on VoIP availability.
Some providers initially just gave their customers phone numbers with codes of big cities no matter where their customers are or where they will use their VoIP-connection. But it was soon banned as in that case it makes no sense to use telephone area codes, since it becomes impossible to include a phone number to a specific city.
At the present it is allowed to give out these codes only to those customers who actually live in these areas. Large costs are the basis for why VoIP providers do not offer phone numbers from all phone lines, despite the fact that it is permitted.
Alternatively, providers offer to use the numbers 0180, which are available for calls from landlines or mobile phones.