Question: when did they stop using letters in phone numbers

title: Telephone number
text: In the most areas of North America , telephone numbers in metropolitan communities consisted of a combination of digits and letters , starting in the 1920s until the 1960s . Letters were translated to dialed digits , a mapping that was displayed directly on the telephone dial . Each of the digits 2 to 9 , and sometimes 0 , corresponded to a group of typically three letters . The leading two or three letters of a telephone number indicated the exchange name , for example , EDgewood and IVanhoe , and were followed by 5 or 4 digits . The limitations that these system presented in terms of usable names that were easy to distinguish and spell , and the need for a comprehensive numbering plan that enabled direct - distance dialing , led to the introduction of all - number dialing in the 1960s . 

Answer: answer: In the most areas of North America, telephone numbers in metropolitan communities consisted of a combination of digits and letters, starting in the 1920s until the 1960s. The limitations that this system presented in terms of usable names that were easy to distinguish and spell led to the introduction of all-number dialing in the 1960s.