Telephone line

For the Electric Light Orchestra song, see Telephone Line (song).
Utility pole with electric lines (top) and telephone cables.
Fixed telephone lines per 100 inhabitants, 1997–2007.
Cross section of telephone cable of 1,800 twisted pairs, 1922.

A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system.[1] It is designed to reproduce speech of a quality that is understandable.[2] 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 billing purposes reserved for that user.

Telephone lines are used to deliver landline telephone service and digital subscriber line (DSL) phone cable service to the premises.[3] Telephone overhead lines are connected to the public switched telephone network.[4][5] 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.

  1. ^ Telephones. U.S. Government Printing Office. 1910.
  2. ^ "Telephone Circuits". ScienceDirect. Retrieved 2022-12-12.
  3. ^ Pizzi, Skip; Jones, Graham (2014-04-24). A Broadcast Engineering Tutorial for Non-Engineers. CRC Press. p. 18. ISBN 978-1-317-90683-4.
  4. ^ Staff, Cia Training Ltd (2003-04-01). Ecdl/Icdl Syllabus 4 Module 1 Basic Concepts of IT: European Computer Driving Licence. CIA Training Ltd. p. 35. ISBN 978-1-86005-123-4.
  5. ^ "Get phone number from Facebook". lucidgen.com (in Vietnamese). 2019-04-28. Retrieved 2024-08-15.