Telephone numbers in India operator as well as the service and the company. Telemarketers have been issued 10-digit telephone numbers starting with 140 (140XXXXXXX) by the Department of Telecommunications on TRAI's request. 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.
All-figure dialling in the London telephone area a subscriber number on the Wimbledon exchange was presented WIM 1234 and dialled as 946 1234. These local exchange codes (introduced in London in 1927) predated the introduction of STD codes by several decades. The continued operation of the system presented a number of problems. With the growth of subscriber dialled international calls from abroad and the incompatible allocation of letters to numbers on foreign dials, there was an increase in the number of dialling errors. In London the number of three letter codes that could be used to represent exchanges had been exhausted. Significant