A cordless telephone or portable telephone has a portable telephone handset that connects by radio to a base station connected to the public telephone network. The operational range is limited, usually to the same … 展开

Radio telephony (telephony without wires) predated cordless phones by at least two decades. The first, MTS, or Mobile Telephone Service went into service in 1946. Because the range … 展开

Many cordless phones in the 21st century are digital. Digital technology has helped provide clear sound and limit casual eavesdropping. Many cordless phones have one main base station and can add up to three or four additional bases. This allows for multiple voice … 展开

Roaming cordless phone handsets exist which are not tethered to any particular base station, but which also do not use traditional mobile (cellular) phone networks. These most commonly use digital technologies like DECT, 2.4 GHz unlicensed spectrum, or 展开

United States
In the United States, seven frequency bands have been allocated by the Federal Communications Commission for uses that include cordless phones. These are:
• 1.7 MHz (1.665–1.770 MHz, narrow-band FM) Cordless … 展开

Many analog phone signals are easily picked up by radio scanners, allowing anyone within range to listen in on conversations (though this is illegal in many countries). Though many such analog models are still produced, modern digital technology is … 展开

• Carterfone
• Fixed-Mobile Convergence Alliance
• Personal Handy-phone System (PHS) in Japan and China
• Spread spectrum 展开