The “prefix” 555 was established as the Entertainment DID range sometime around the late 40’s by At&t or as they were called back then “Ma Bell”.

DID stands for Direct Inbound Dial. That range was targeted for a busy signal.
Therefore as time went on most curious idiots would get the clue that when they see 555 its a fake number.
Overtime most people knew if they called a 555 number other than 555-1212 they would get a busy signal. Classic conditioning.

Remember At&t is run by X-Military.

The one I heard was when phone numbers were first developed, the idea was the first 3 numbers were an extension of the last name. Therefore, someone “Campea, John” would have number beginning with 226 (CAM).

The reason 555 was chosen was there was no last name that would start with the 3 letter combination of j,k,l. 777 wasn’t used because of names like “Spright”. But I don’t know my 999 wasn’t also considered, unless some guy is named Zywig.

Again, it may or may not be true but when I researched this a few years ago that is what I found.

Also, some 555 numbers are actually used now. Sadly, some kids cartoons from the 80’s and 90’s use 555 numbers that call porn hotlines now…

The reason movies/tv use the 555 prefix for their numbers has nothing more to do with the fact that it used to not be a legitimate exchange. All exchanges in the US and Canada are designated as a city code, and the 555 was never associated with in until (I believe) the 80’s, as mass population growth warranted the use. Anyways, it’s still fun to know the little things.

BTW, if you dial 800-555-1212 you get a directory assistance for 800 numbers in both countries…

Cheers

i blogged this back in april as well.. its a great movie piece.

Interesting. I always wondered about that.