Post says it all
In: 140
From the introduction of the phone until the 1990’s most phone numbers in the UK were shown as an exchange name and number. E.g. London 12345. The number of digits depended upon the number of subscribers, small exchanges with less than 10 subscribers might have single digit numbers e.g. Aberfouldy 7.
In these areas you could dial local numbers without an exchange (just dial 7) or if you wanted ‘long distance’ you would dial the operator ‘0’ and give the exchange and number. They would ‘patch you through’ using a big plug board to another operator who would make the final connection.
Of course as more people had phones this became a problem. Going from 10 people on an exchange to 11 meant adding a digit to everyone’s local number, so Aberfouldy 7 became Aberfouldy 17 etc.
Exchanges started becoming mechanical dispensing with operators. Each exchange was given national dialling codes. You could still dial the local number, but you could also dial the national number (prefixed with zero). So to dial London 12345 you would dial 01-12345.
In the 1980’s this was getting difficult to manage, 3 digit local numbers were changed to 4 digit, 4 to 5 etc. as the number of lines were increased (although one local one digit phone number in Scotland survived until 1990.
This is just a summary, there were many changes and systems but suffice to say by 1980’s it was clear numbers were running out for both national and local numbers.
Fax machines, non-geographic numbers, pagers all added to the problem.
In 1995 ‘PhONEe day’ put a ‘1’ in front of all national numbers ( I won’t go into the contortions that were needed to change London numbers from the 01 national code). This freed up the 07, 08, and 09 numbers for later use.
Now 07 numbers are reserved for mobile devices (which have 10 digits) so there are up to 10,000,000,000 possible numbers, so enough for every person in the UK to have over 150 mobile phones.
Latest Answers