Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
Telephone line
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
{{Short description|Single-user circuit on a telephone communication system}} {{For|the Electric Light Orchestra song|Telephone Line (song)}} [[Image:Phone pole3.jpg|thumb|right|[[Utility pole]] with electric lines (top) and telephone cables.]] [[File:Fixed telephone lines per 100 inhabitants 1997-2007 ITU.png|thumb|Fixed telephone lines per 100 inhabitants, 1997–2007.]] [[File:Bell telephone magazine (1922) (14754023254).jpg|thumb|upright|Cross section of telephone cable of 1,800 twisted pairs, 1922.]] [[File:Telephone cable.jpg|thumb|A newer telephone cable used to carry telephone lines from several customers]] A '''telephone line''' or '''telephone circuit''' (or just '''line''' or '''circuit''' industrywide) is a single-user [[telecommunication circuit|circuit]] on a telephone [[telecommunication|communication]] system.<ref>{{Cite book |url=https://books.google.com/books?id=wi4wAAAAYAAJ&dq=A+%22telephone+line%22+or+telephone+circuit+(or+just+line+or+circuit+industry+wide)+is+a+single-user+circuit+on+a+telephone+communication+system.&pg=PP79 |title=Telephones |date=1910 |publisher=U.S. Government Printing Office |language=en}}</ref> It is designed to reproduce speech of a quality that is understandable.{{fact|date=February 2025}} It is the physical [[wire]] or other signaling medium connecting the user's telephone apparatus to the [[telecommunications]] network, and usually also implies a single telephone number for [[invoice|billing]] purposes reserved for that user. Telephone lines are used to deliver consistent [[landline]] telephone service and digital subscriber line (DSL) phone cable service to the premises.<ref>{{Cite book |last1=Pizzi |first1=Skip |url=https://books.google.com/books?id=sQ1xAwAAQBAJ&dq=Telephone+lines+are+used+to+deliver+landline+telephone+service+and+digital+subscriber+line+(DSL)+phone+cable+service+to+the+premises.&pg=PA18 |title=A Broadcast Engineering Tutorial for Non-Engineers |last2=Jones |first2=Graham |date=2014-04-24 |publisher=CRC Press |isbn=978-1-317-90683-4 |pages=18 |language=en}}</ref> Telephone overhead lines are connected to the public switched telephone network.<ref>{{Cite book |last=Staff |first=Cia Training Ltd |url=https://books.google.com/books?id=cup9bFZfK7EC&dq=Telephone+overhead+lines+are+connected+to+the+public+switched+telephone+network.&pg=PA35 |title=Ecdl/Icdl Syllabus 4 Module 1 Basic Concepts of IT: European Computer Driving Licence |date=2003-04-01 |publisher=CIA Training Ltd. |isbn=978-1-86005-123-4 |pages=35 |language=en}}</ref><ref>{{Cite web |date=2019-04-28 |title=Get phone number from Facebook |url=https://lucidgen.com/tim-so-dien-thoai-tu-facebook/ |access-date=2024-08-15 |website=lucidgen.com |language=vi}}</ref> The [[voltage]] at a subscriber's network interface is typically 48 V between the ring and tip wires, with tip near ground and ring at –48 V. == In the United States == In 1878, the [[Bell System|Bell Telephone Company]] began using two-wire circuits, called the [[local loop]], from each user's telephone to [[Telephone exchange|end office]]s, which performed any necessary electrical switching to allow voice signals to be transmitted to more distant telephones. These wires were typically [[copper]], although [[aluminium]] has also been used, and were carried in [[balanced pair]]s of open wire, separated by about 25 cm (10″) on [[utility pole|poles]] above the ground, and later as [[twisted pair]] cables. Modern lines may run underground and may carry analog or digital signals to the exchange. They may also have [[Subscriber Loop Carrier|a device that converts]] the [[analog signal]] to digital for [[transmission (telecom)|transmission]] on a [[carrier system]]. Often, the customer end of that wire pair is connected to a [[data access arrangement]], and the telephone company end of that wire pair is connected to a [[telephone hybrid]]. In most cases, two [[copper wire]]s ([[tip and ring]]) for each telephone line run from a home or other small building to a local [[telephone exchange]]. There is a central [[junction box]] for the building where the wires that go to telephone jacks throughout the building and wires that go to the exchange meet and can be connected in different configurations depending upon the subscribed telephone service. The wires between the junction box and the exchange are known as the [[local loop]], and the network of wires going to an exchange is known as the [[access network]]. The vast majority of houses in the U.S. are wired with 6-position [[modular connector|modular jacks]] with four [[electrical conductor|conductors]] ([[6P4C]]) wired to the house's junction box with copper wires. Those copper wires may be connected back to two telephone overhead lines at the local [[telephone exchange]], thus making those jacks [[RJ11, RJ14, RJ25|RJ14]] jacks. More often, only two of the wires are connected to the exchange as one telephone line, and the others are unconnected. In that case, the jacks in the house are [[RJ11, RJ14, RJ25|RJ11]]. Older houses often have 4-conductor telephone station cable in the walls color coded with Bell System colors: red, green, yellow, and black as 2-pairs of 22 AWG (0.33 mm<sup>2</sup>) solid copper; "line 1" uses the red/green pair and "line 2" uses the yellow/black pair. Inside the walls of the house—between the house's outside junction box and the interior [[wall jack]]s—the most common telephone cable in new houses is [[Category 5 cable]]—4 pairs of 24 AWG (0.205 mm<sup>2</sup>) solid copper.<ref>Public Service Commission of Wisconsin.[http://www.wwt.net/pdf/telephone-wiring.pdf "Testing, Repairing & Installing Home Telephone Wiring"] {{Webarchive|url=https://web.archive.org/web/20180328173511/http://wwt.net/pdf/telephone-wiring.pdf|date=2018-03-28}}.</ref> Inside large buildings, and in the outdoor cables that run to the telephone company [[point of presence|POP]], many telephone lines are bundled together in a single cable using the [[25-pair color code]].<ref>{{cite book |last1=Bigelow |first1=Stephen J. |title=Telephone Repair Illustrated |date=1993 |publisher=TAB Books |isbn=978-0-8306-4034-8 |oclc=26632919 }}{{pn|date=February 2025}}</ref> Outside plant cables can have up to 3,600 or 3,800 pairs, used at the entrances of telephone exchanges.<ref>{{cite journal |last1=Wilkens |first1=W.D. |title=Telephone cable: overview and dielectric challenges |journal=IEEE Electrical Insulation Magazine |date=March 1990 |volume=6 |issue=2 |pages=23–28 |doi=10.1109/57.50802 }}</ref><ref>{{Cite book |last=Shoult |first=Anthony |url=https://books.google.com/books?id=or08gGGX_toC&dq=3800+pair+telephone+cable&pg=PA469 |title=Doing Business with Saudi Arabia |date=2006 |publisher=GMB Publishing Ltd |isbn=978-1-905050-67-3 |language=en}}</ref> == References == {{Reflist}} == External links == * {{Commons category-inline}} <!-- Is [[BS 6312]] used in the UK ? --> {{DEFAULTSORT:Telephone Line}} [[Category:Local loop]] [[Category:Telecommunications equipment|Line]] [[Category:Telecommunications infrastructure]]
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)
Pages transcluded onto the current version of this page
(
help
)
:
Template:Cite book
(
edit
)
Template:Cite journal
(
edit
)
Template:Cite web
(
edit
)
Template:Commons category-inline
(
edit
)
Template:Fact
(
edit
)
Template:For
(
edit
)
Template:Pn
(
edit
)
Template:Reflist
(
edit
)
Template:Short description
(
edit
)
Template:Webarchive
(
edit
)