What year was 4 digit phone numbers used?

Answer 1

Telephone numbers started as one or two digits. Then, they had to add an exchange as local subscribers increased.

In the USA, they used a name exchange+ personal number, with the name being an area in a town/city. The name-exchange was an easy way for customers to recall the exchange. For example, Able-5555. Locally, the name was further abbreviated, such as AB-5555 for Able-5555. When making a call when only operators connected the call, you'd just give the local name (exchange) of Able with the personal number (ex. 5555). Later, you could dial AB-5555.

By the 1960s, rural towns/cities went to a number as the exchange in place of the name. So, 555-5555. Larger towns/cities might have converted earlier.

The 7-digit numbers stayed until about the 1990s when telephone companies required area code+exchange+personal number.

Answer 2

That depended on where you were and the type of telephone exchange equipment used in your area. Some communities never had 4 digit numbers as their first automatic dialing equipment was installed with 5, 6, or 7 digit numbers.

My personal research on the telephone system here shows one small town in the state had 4 digit phone numbers in 1942 (probably earlier than that) while most of the cities in the state were still using manual exchanges. Most of the cities originally got 5 digit phone numbers around 1952. The capital city originally got 7 digit phone numbers in 1955, with the majority of telephone exchanges in the state being upgraded from their original 4 or 5 digit phone numbers to standardized 7 digit phone numbers in either 1955 or 1956. In cities in several nearby states 6 digit phone number were in use in 1954 (probably earlier than that) until being upgraded to standardized 7 digit phone numbers at various times between 1956 and 1959. Direct Dialed Long Distance using the 3 digit area code was not available in this state until 1961 (and even then you still couldn't directly dial some parts of the country for another few years).

Answer 3

1964