area number
Area code designation is a numerical designation of regional subnetworks.
The area codes are defined by the Numbering Ordinance and include private networks, mobile networks, personal services, tariff-free services, services with regulated tariff ceilings, and freely calculable value-added services. For international numbers, the country code is followed by the regional code or the area code. The national number contains the regional code or area code and the subscriber number.
The assignment of area codes is subject to certain conditions. For example, a private network must be distributed over several locations. Area codes have five or six digits and begin with special combinations of digits.