Geek Trivia: Strength in (phone) numbers

What potentially real 555 telephone number does Hollywood continue to use in movies and television shows -- even though it's no longer on the list of reserved fake phone numbers?

What potentially real 555 telephone number does Hollywood continue to use in movies and television shows — even though it's no longer on the list of reserved "fake" phone numbers — largely out of a tradition that predates 10-digit phone numbers themselves?

The quasi-fake telephone number that Hollywood just can't give up is 555-2368, which is decidedly outside the 555-0100 to 555-0199 range of reserved fictional dialing codes.

Many of you may recognize this as the "Who ya gonna call?" hotline used to reach The Ghostbusters. It's also the professional phone number to reach private detective Jim Rockford, the home phone of bionic woman Jaime Sommers, the Guilers' home phone from Close Encounters of the Third Kind, the number of a motel room in Memento, and the desk phone of police detectives Tony Baretta, Rick Hunter, and Theo Kojak, all of whom had shows titled after their last names. This list is far from exhaustive but should serve to illustrate just how popular this fictional phone number was and continues to be, especially considering that it stopped being certifiably fake after 1994.

So what, exactly, makes this particular fake number so popular with Hollywood writers and producers? Tradition.

Before 10-digit dialing codes, the U.S. phone numbers employed letter-number combinations formatted as two letters, followed by as many as four numbers. The two-letter prefixes were extended into memorable colloquial names, such as Butterfield for BU (as in the film, Butterfield-8). During this period, the KL exchange was reserved for fictional use, resulting in famous fake telephone numbers like Klondike 5-4385, the number for Doc Emmett Brown's 1955 home in Back to the Future. That said, the KL exchange was not the preferred choice for many writers of fiction (and fictional phone numbers).

AT&T maintained a Central Exchange in every major metropolitan area for most of the mid 20th century and advertised the contact number of these exchanges rather heavily: Exchange-2368. The 2368 was the numeric conversion of CENT, for central, using the letters assigned to digits on a telephone dial. Thus, when writers would "invent" phone numbers, they would often end them with 2368 so they would sound familiar and plausible, thanks to the phone company's promotion of Exchange-2368.

When the 10-digit, 555 fictional phone number era came into use in the late 1960s and early 1970s, writers simply converted Exchange-2368 to 555-2368, preserving the traditionally fake phone number. That tradition continues today, even though real people could conceivably apply for the 555-2368 number in various U.S. area codes.

That's not just some interacting integration of insularly important integers; it's a numerically notorious notion of noteworthy Geek Trivia.

The quibble of the week

If you uncover a questionable fact or debatable aspect of this week's Geek Trivia, just post it in the discussion area of the article. Every week, yours truly will choose the best quibble from our assembled masses and discuss it in a future edition of Geek Trivia.

This week's quibble comes from the Sept. 16, 2008 edition of Geek Trivia, "The fact of the (anti)matter." TechRepublic member Dr_Zinj dinged me for misrepresenting the current state of antimatter containment technology. Check out this week's quibble.


Jay Garmon has a vast and terrifying knowledge of all things obscure, obtuse, and irrelevant. One day, he hopes to write science fiction, but for now he'll settle for something stranger — amusing and abusing IT pros. Read his full profile. You can a...

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