Telephone lines are fixed telephone lines that connect a subscriber's terminal equipment to the public switched telephone network and that have a port on a telephone exchange.
A fixed line was originally an overland telegraph wire, as opposed to an undersea cable. Currently, it refers to a telephone line which travels through a solid medium, either metal wire or optical fibre, as distinguished from a mobile cellular line, where transmission is via radio waves. Landlines usually have a lower price for calling time, and the user hardware costs less than mobile phones, but they are less convenient. A landline is also used to increase the security of communications, as it cannot be intercepted by a receiver without physical access to the line.
In 2008 there were 1.27 bil fixed line subscribers in the world.
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