In these areas, the service is available inside buildings as well, bearing in mind that signal strength is significantly influenced by the proximity of windows, the material buildings are made of (e.g. reinforced concrete and stained glass significantly weaken reception), as well as the fact that signal strength increases with height. Surrounding buildings may also weaken reception.
The service is available only with an outdoor antenna, without which the coverage area decreases to about one quarter. Along rural roads and in smaller towns, only vehicle-installed terminals work appropriately. Naturally, these areas, too, may feature buildings where, at certain locations within, mobile phones will work properly.