When telephone numbers were first used they were very short, from one to three digits, and were communicated orally to a switchboard operator when initiating a call. As telephone systems have grown and interconnected to … See more

In the middle 20th century in North America when a call could not be completed, for example because the phone number was not assigned, had been disconnected, or … See more

Fictitious telephone numbers are often used in films and on television to avoid disturbances by calls from viewers. For example, The United States 555 (KLondike-5) exchange code … See more

• ITU-T Recommendation E.123: Notation for national and international telephone numbers, e-mail addresses and Web addresses
• RFC 3966 The tel: URI for telephone numbers
• History of UK dialing codes, with lists of codes and more links See more

United States
In the late 1870s, the Bell interests started utilizing their patent with a rental scheme, in which they would rent their instruments to individual users who would contract with other suppliers to connect them; for example from home … See more

Telephone numbers are sometimes prefixed with special services, such as vertical service codes, that contain signaling events other than numbers, most notably the star (*) and the number sign (#). Vertical service codes enable or disable special telephony … See more

• Category:Telephone numbers by country
• Geographic number
• List of country calling codes See more