Prompted by a conversation I had with Bill earlier today.
something I have been asked by people in England: Why does almost everybody in American movies and TV shows have a telephone number that starts with 555 ?
So for everybody, including perhaps the younger of you in America who aren't aware of the development of telephone switching, here's a brief explanation.
When direct-distance dialing was being introduced in the 1950s, all local numbers had to be made up to 7 digits, the first three being the central-office code. The system which was adopted as standard was the 2-letter, 5-number system, where the 3-digit prefix was listed as 2 letters plus a single digit. This system was already in use in many large cities which had used 7-digit numbers for many years (e.g. the famous PEnnsylvania 6-5000 in New York City, immortalized by Glenn Miller's recording).
The digit 5 corresponds to the letters JKL, which severely restricted the number of exchange names which could made up for the codes 55x. Thus the prefixes 55x were rarely, if ever assigned in any area code (some places used a couple of 55x codes for mobile phones and other special purposes).
So it was that the prefix 555 was free and was therefore a handy choice for TV and movie producers who wanted to display reasonable looking numbers without fear that they were showing a number which actially belonged to someone. (Did anybody really believe that by calling the number shown they could actually talk to Lt. Kojak or Chief Ironside?
I suppose they must have done!)
In some older shows, a number is actually displayed using about the only name which can be made from the JKL combination -- KLondike.
Ma Bell herself even got in on the act. Look at many old ads for telephones and you'll see the number on the dial is 555-2368. They even included "area code" 311, which was a reserved service code, at that time unused.
The only "real" 555 number is that which was assigned in every area code throughout the country, 555-1212 for directory assistance. Although always advertised as 555-1212, in many areas years ago dialing into the area with 555 plus any 4 digits got you information.
I believe that some areas have now actually started assigning some genuine 555 numbers.
OK, off-topic trivia over.
This is a recording....