An emergency telephone is a phone

Telephone

The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...

 specifically provided for making calls to emergency services and is most often found in a place of special danger or where it is likely that there will only be a need to make emergency calls.

Emergency telephones are commonly found alongside major roads and on university campuses

Campus university

A campus university is a British term for a university situated on one site, with student accommodation, teaching and research facilities, and leisure activities all together...

 throughout the world. In the United Kingdom, orange "SOS" call boxes are spaced at 1 miles (1.6 km) intervals on all motorways as well as some major "A" roads, with roadside markers indicating the nearer phone. Emergency telephones were installed at 0.25 miles (402.3 m) intervals on all limited-access highways ("Freeways") throughout Southern California

Southern California

Southern California is a megaregion, or megapolitan area, in the southern area of the U.S. state of California. Large urban areas include Greater Los Angeles and Greater San Diego. The urban area stretches along the coast from Ventura through the Southland and Inland Empire to San Diego...

 in the United States as far back as the 1970s. On Italian "Autostrade" ("Motorways"), "SOS" emergency phones, generally coloured in yellow, are found spaced at 2 kilometres (1.2 mi) intervals.

Emergency phones can also be found at the ends of bridges or near cliffs which have a history of suicide

Suicide

Suicide is the act of intentionally causing one's own death. Suicide is often committed out of despair or attributed to some underlying mental disorder, such as depression, bipolar disorder, schizophrenia, alcoholism, or drug abuse...

s. These are generally routed directly to appropriate support agencies such as The Samaritans in the UK

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

.

They are also occasionally found along the coastline where members of the public may wish to report swimmers or boats in danger at sea. In the UK such phones connect directly to the Coastguard

Her Majesty's Coastguard

Her Majesty's Coastguard is the service of the government of the United Kingdom concerned with co-ordinating air-sea rescue.HM Coastguard is a section of the Maritime and Coastguard Agency responsible for the initiation and co-ordination of all civilian maritime Search and Rescue within the UK...

.

In some countries, they are also found in places where people may feel vulnerable or unsafe at night. They are commonly found on university

University

A university is an institution of higher education and research, which grants academic degrees in a variety of subjects. A university is an organisation that provides both undergraduate education and postgraduate education...

 campus

Campus

A campus is traditionally the land on which a college or university and related institutional buildings are situated. Usually a campus includes libraries, lecture halls, residence halls and park-like settings...

es. These are generally linked to security companies who patrol the streets where the phones are located.

As cell phone use continues to increase, the need for emergency telephones declines and they are being phased out in many cities. However, they are likely remain vital for safety in areas with poor cell phone coverage and in places of high suicide risk.

These telephones are almost always marked by a placard or sign indicating a unique serial number or identifier which allows the authorities to know exactly where the caller is - even if the caller does not know - by having the caller read the short identifier from the placard over the telephone. Some phones are equipped with the equivalent of caller id

Caller ID

Caller ID , also called calling line identification or calling number identification or Calling Line Identification Presentation , is a telephone service, available in analog and digital phone systems and most Voice over Internet Protocol applications, that transmits a caller's number to...

 and the agent receiving the call can identify the location even if the caller cannot. In most U.S. states with call boxes, the call box placard has the route's milepost reading. In California, call boxes are identified by their mileage through individual counties using postmiles

California postmile

California uses a postmile system on all of its state highways, including U.S. Routes and Interstate Highways. The postmile markers indicate the distance a route travels through individual counties, as opposed to mile markers that indicate the distance traveled through a state.-Format:A postmile...

for reference. Each box has a 2-letter identifier for the county, followed by the route number, then a 3 or 4 digit number corresponding to the route's postmileage in tenths of miles.