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#23958 - 04/01/03 05:15 PM Telephone Trivia: Why 555 ?  
pauluk  Offline
Joined: Aug 2001
Posts: 7,520
Norfolk, England
Prompted by a conversation I had with Bill earlier today.

This is 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? [Linked Image] 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.... [Linked Image]

Work Gear for Electricians and the Trades

#23959 - 04/01/03 05:48 PM Re: Telephone Trivia: Why 555 ?  
Trainwire  Offline
Joined: Mar 2002
Posts: 360
I always thought the number was

[Linked Image]

(Now we will see who really is the "old fogy") [Linked Image]

#23960 - 04/01/03 08:27 PM Re: Telephone Trivia: Why 555 ?  
Bjarney  Offline
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
For more intensely useful telephone-exchange info, see

I think ‘they’ have further restricted "movie" numbers to between 555-0100 and 555-0199 nowadays.

#23961 - 04/01/03 08:55 PM Re: Telephone Trivia: Why 555 ?  
DBC1  Offline
Joined: Mar 2003
Posts: 16
Tulsa, OK USA
555 prefix is a reserved VPN for ATT.

#23962 - 04/01/03 08:57 PM Re: Telephone Trivia: Why 555 ?  
ThinkGood  Offline
Joined: Aug 2002
Posts: 1,081
Milwaukee, WI
Eight-Six-Seven-Five, Three-O-Nayayn...

#23963 - 04/01/03 10:10 PM Re: Telephone Trivia: Why 555 ?  
Bill Addiss  Offline
Joined: Oct 2000
Posts: 3,878

Ah, it makes sense now.
KLondike-5 sounds familiar too.

[Linked Image]

#23964 - 04/01/03 10:17 PM Re: Telephone Trivia: Why 555 ?  
harold endean  Offline
Joined: Feb 2002
Posts: 2,233
Boonton, NJ
Actually, I believe the reason for 555 was because that is a dead number. No matter what you dial, (555-1234 or 555-5678) you will not get connected. The Telco would set aside certain numbers for testing. There use to be a way where I could dial 550 plus the last four digits of my home phone and then hang up. The Telco equipment would send back a signal that would ring my phone. This was one way the Telco would check to see if the phone worked properly. There was another 551 or 552 plus the last 4 digits to check for rings, busy signals, etc. Now with all the new modern stuff, I amnot sure if all this stuff works anymore. By the way, I was told that if you go to Google,com and insert your telco number, it will pop up your home address. WITH a map if you ask for it. Pretty scary huh!

#23965 - 04/01/03 10:43 PM Re: Telephone Trivia: Why 555 ?  
Bill Addiss  Offline
Joined: Oct 2000
Posts: 3,878

I've used the Reverse lookups for years, to verify Telephone #s with people and addresses.

Here's a Link to an Address Lookup. Enter an Address and it will tell you who lives there and the Telephone #.


#23966 - 04/01/03 11:39 PM Re: Telephone Trivia: Why 555 ?  
Bjarney  Offline
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
Another useful number 1.700.555.4141 spits back your LD carrier.

#23967 - 04/02/03 12:18 AM Re: Telephone Trivia: Why 555 ?  
Electric Eagle  Offline
Joined: Apr 2002
Posts: 914
Alpharetta, GA
Whever someone who asks for my telephone number that doesn't need my number
(Radio Shack, Great Clips, etc.), I tell them 770 555-1212. You should see the funny look on their face when they realise that I just told them to call information for area code 770.

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