Out of range means a mobile phone cannot receive base station signals, preventing calls and data communication. The screen displays "Out of Range" or "No Service." It occurs in mountains, tunnels, underground facilities, deep inside buildings, and at sea where signals physically cannot reach.
Three main causes exist. First, excessive distance from base stations. Second, signal blocking by concrete, steel frames, or terrain. Third, network congestion during major events or disasters when connections exceed base station capacity, creating effectively out-of-range conditions.
Calling an out-of-range phone triggers the message: "The number you have dialed is either out of range or powered off." Emergency calls (110/119) also fail in this state, so sharing plans beforehand is critical for activities in signal-poor areas like hiking or underground work.
Wi-Fi Calling enables calls over Wi-Fi when cellular signals are unavailable. Femtocells (small base stations) can improve home coverage. Carriers accept signal improvement requests for persistently poor coverage areas.