Telephone numbers in India Telephone numbers in India Telephone numbers in India are administered under the "National Numbering Plan of 2003" by the Department of Telecommunications. The numbering plan was last updated in 2015. The International Telecommunication Union has assigned the country calling code "91" to India. Subscriber Trunk Dialling (STD) codes are assigned to each city/town/village, with the larger Metro cities having shorter area codes (STD codes), which are from 2 to 8 digits long. For example, Tier-2 Cities or culturally significant towns in India have STD code with 3 digits. For example, Kanpur and Lucknow were the two cities between which the
Telephone keypad the following system: These letters have been used for multiple purposes. Originally, they referred to the leading letters of telephone exchange names. In the mid-20th century United States, before the switch to All-Number Calling, telephone numbers had seven digits including a two-digit prefix which was expressed in letters rather than digits, e.g.; KL5-5445. The UK telephone numbering system used a similar two-letter code after the initial zero to form the first part of the subscriber trunk dialling code for a region. For example, Aylesbury was assigned 0AY6, which translated into 0296. The letters have also been used, mainly in the