Landline

A landline (land line, land-line, main line, fixed-line, and wireline) is a telephone connection that uses metal wires from the owner's premises also referred to as: POTS, Twisted pair, telephone line or public switched telephone network (PSTN).

Landline services are traditionally provided via an analogue copper wire to a telephone exchange. Landline service is usually distinguished from other more modern forms of telephone services which use Internet Protocol based services over optical fiber (Fiber-to-the-x) or other broadband services (VDSL/Cable) using Voice over IP, although sometimes modern fixed phone services delivered over a fixed internet connection are sometimes referred to as a landline (non-cellular service).

Characteristics
Landline service is typically provided through the outside plant of a telephone company's central office, or wire center. The outside plant comprises tiers of cabling between distribution points in the exchange area, so that a single pair of copper wire, or an optical fiber, reaches each subscriber location, such as a home or office, at the network interface. Customer premises wiring extends from the network interface ("NID") to the location of one or more telephones inside the premises.

A subscriber's telephone connected to a landline can be hard-wired or cordless and typically refers to the operation of wireless devices or systems in fixed locations such as homes. Fixed wireless devices usually derive their electrical power from the utility mains electricity, unlike mobile wireless or portable wireless, which tend to be battery-powered. Although mobile and portable systems can be used in fixed locations, efficiency and bandwidth are compromised compared with fixed systems. Mobile or portable, battery-powered wireless systems can be used as emergency backups for fixed systems in case of a power blackout or natural disaster.

Other aspects of landline is the ability to carry high-speed internet popularly known as Digital subscriber line (DSL) which links back to the digital subscriber line access multiplexer (DSLAM) within the central office, T-1/T-3, or ISDN.

Usage and statistics
In 2003, the CIA World Factbook reported approximately 1.263 billion main telephone lines worldwide. China had more than any other country, at 350 million, and the United States was second with 268 million. The United Kingdom had 23.7 million residential fixed home phones.

A 2013 International Telecommunication Union report showed that the total number of fixed-telephone subscribers in the world was about 1.26 billion.

In many parts of the world, including Africa and India, the growth in mobile phone usage has outpaced that of landlines. In the United States, while 45.9 percent of households still had landlines as of 2017, more than half had only mobile phones. This trend is similar in Canada, where more than one in five households used mobile phones as their only source for telephone service in 2013. However, voice over IP (VoIP) services offer an alternative to traditional landlines, allowing numbers to remain in use without being tied to a physical location, making them more adaptable to modern ways of working. The FCC maintains both landline and Voice over IP subscriber numbers to monitor long term trends in usage.

2000s
In many countries, landline service has not been readily available to most people. In some countries in Africa, the rise in cell phones has outpaced growth in landline service. Between 1998 and 2008, Africa added only 2.4 million landlines. In contrast, between 2000 and 2008, cell phone use rose from fewer than 2 in 100 people to 33 out of 100. There has also been a substantial decline of landline phones in the Indian subcontinent, in urban and even more in rural areas.

In the early 21st century, installations of landline telephones has declined due to the advancement of mobile network technology and the obsolescence of copper wire networking. It is more difficult to install landline copper wires to every user than it is to install transmission towers for mobile service that many people can connect to. Some predict that these metallic networks will be deemed completely out of date and replaced by more efficient broadband and fiber optic landline connections extending to rural areas and places where telecommunication was much more sparse. In 2009, The Economist wrote "At current rates the last landline in America will be disconnected sometime in 2025."

In 2004, only about 45% of people in the United States between the ages of 12 and 17 owned cell phones. At that time, most had to rely on landline telephones. Just 4 years later, that percentage climbed to about 71%. That same year, 2008, about 77% of adults owned a mobile phone.

2010s
In the year 2013, 91% of adults in the United States owned a mobile phone. Almost 60% of those with a mobile had a smartphone. A National Health Interview Survey of 19,956 households by the Centers for Disease Control and Prevention released May 4, 2017 showed 45.9 percent of U.S. households still had landlines, while 50.8 percent had only cell phones. Over 39 percent had both.

In Canada, more than one in five of households use cell phones as their only source for telephone service. In 2013, statistics showed that 21% of households claimed to only use cellular phones. Households that are owned by members under the age of 35 have a considerably higher percentage of exclusive cell phone use. In 2013, 60% of young household owners claimed to only use cell phones. In 2019, 54% of Canadian households and 80% of French households had a landline telephone.

2020s
In June 2020, it was reported that 60% of Australian adults used only mobile phones, with no landline. In 2021, only 14.5% of Australian and 29.4% of American households used landline at home. In contrast, 73% of UK households still used landline in 2020. In 2022, 82.9% of German households had at least one landline phone while 73 percent of U.S. households had only a cell phone, 25 percent had a landline and cell service, and 1 percent had only a landline.

Estonia and the Netherlands have retired the legacy parts of the public switched telephone network (PSTN). In the United Kingdom, the analogue copper landline network is due to be terminated in 2025. The VoIP replacement is known as "Digital Voice" (on a BT service) in the UK. France, Germany and Japan are also in the process of replacing theirs.

By means of porting, voice over IP services can host landline numbers previously hosted on traditional fixed telephone networks. VoIP services can be used anywhere an internet connection is available on many devices including Smartphones, giving great flexibility to where calls may be answered and thus facilitating remote, mobile and home working, for example. VoIP porting allows landline numbers to remain in use, whilst freeing them from actual landlines tied to one location. This is useful where landline numbers are believed to be preferred by callers, or where it is preferable that legacy landline numbers remain connected.