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What is this?

Telephone numbers used to begin with two letters, which were an abbreviation for a word. For example, there was a Glenn Miller song called PEnnsylvania 6-5000, and Liz Taylor made a movie called BUtterfield-8. I'm just barely old enough to remember that my phone number at home when I was 5 or so started with SYcamore 4, or SY4. These were telephone exchanges, and had exchange names -- PEnnsylvania, SYcamore, KLondike, etc.

So, one day I got interested in finding a list of the old exchange names. Since they were used so widely around the country, I assummed that there would be a master list somewhere, that shouldn't be too hard to find. It turned out to be very hard to find, but in response to this project Mark Cuccia, a real expert on the subject of exchange names, sent it to me. This project is an attempt to assemble information about exchange names from a lot of widely spread original sources.

Thanks to Doug Douglass for this image

NEW! Discussion Group

We've finally set up a new place where you can share your memories, discuss the merits, and organize to revive EXchange names. Get help picking your new EXchange name, or finding your historical EXchange.

Join the discussion!

New! Search Our Database!

We've finally redesigned our database!

Ma Bell published a list of Officially Recommended Exchange Names

PDF (Adobe Acrobat) version of the Recommended List (better for printing)

Why do we care?

Partly just perverse curiosity. Partly because we want to resist the increasing trend towards digitizing our lives. Exchange names helped foster a sense of place, and community, in the same way that cities do. They're also a link to our more analog past which is fast slipping away. This archive can also serve as an aid to authors who are setting stories during this period. It can also be a resource for people who wish to give their phone number using an exchange name.

Since I started this project I have been struck by the number of responses we have received from people who have told us that recalling their old exchange names has brought back a lot of good memories -- things that they haven't thought about for years. Many people have also mentioned that they still remember their phone number from when they were very young.

How does this work?

We've collected exchange names from old phone books, and many people have sent many contributions, which we summarize in the "Big Database".

If you'd like to contribute to the project, you might go to your public library and look through old phone books from before 1963 or so, or talk to friends and family, and send your findings to us.

If you happen to be old enough to remember what your exchange name was 33 years ago, send it to us and we'll add it to the list. Or, if you know anyone who was working for Ma Bell back then, who might have some insights into some of the issues below, we'd love to hear from them!

What's your exchange name now?

If you happen to live in the same place you grew up, and you're old enough to remember or have family members who are old enough, then you probably still know your exchange name. But if you're like many people and have moved to a completely different place, you probably have no idea what the exchange names were back then. Along with other local history, this is part of establishing a sense of the place where you live.

If your current phone number uses an exchange that existed back then, then you can use the original exchange name. For example, my parent's phone number hasn't changed since 1946, so their exchange is still SYcamore.

Many people have phone numbers that didn't exist in their area back then, so they can't use a historically correct exchange name. My suggestion is to choose one from Ma Bell's recommended list, which was valid throughout the Bell System. Where I currently live, the 39 exchange did not exist back then, so I've chosen EXport as my current exchange name.

Project News

We're very RETRO

Jeff Vorzimmer wrote a great article for RETRO magazine, a great web 'zine. Thanks Jeff!

We're Cool In OK

'... where the wind comes sweeping down the plain.' John Owchat of the Daily Oklahoman wrote about us in his column, The Ethernaut. Thanks John!

Yahoo Says We're Cool

The Project was recently named by Yahoo as a "Cool Site"! (Chanted: "We're not worthy ...")

LA Times Says We're Newsworthy

Daniel Akst of the Los Angeles Times recently wrote an article about us, and we saved a copy which you can read here.

Thanks Dan!

America's Network Thinks We're Relevant

The September 1st America's Network magazine included an article about the project. They've been serving the telecom industry since 1909. Unfortunately, they want us to pay for reprinting their article, so that won't be happening in this lifetime. Write them and tell them what you think.

Looking for Telephone Art

You might have noticed that these pages are a bit lacking in cool graphics. That's because we don't have any! If you have 50's ad art depicting telephone scenes that you'd like to donate, we'd love to have it! Please send email to

Did you know ...

The face on Mars has now been identified as that of Elvis. Contrary to popular myth, he wasn't buried in his own back yard after all.

Can you still use exchange names?

Yes, although you need to use some common sense. Most people won't recognize them if they're spoken, but can probably figure them out if they're written. Here's some suggestions:

Shock value -- If someone asks for your phone number and you tell them "MUrray 5-3247", they're going to look at you strangely and say "Huh?".

Phone message -- "You've reached KLondike 5-3247 ..."

Retro look -- Business cards, advertisements, invitations, web pages, anywhere you might write them

At last count we've received over 10,000 contributions from people all over the US and Canada. Thanks to everyone who's contributed! Contributions are always welcome! Keeping up with the data coming in requires several hours per week, so unfortunately we've had to give up trying to respond to everyone personally, but we'll try to keep up with getting the contributions into the list. We know that when you send something in it's a little unsettling not to hear anything back, but please try to understand, and check back to see if your contributions are now included. It can take us up to a month to catch up sometimes.

What do we know for sure?

Very little, really. We know that the exchange names listed below were in use in the early 1960's in the areas listed. We know that in the San Francisco bay area that exchange names stopped being published in phone books around 1963, but contributors to the project have told us that they survived into the mid '70's in other areas. In many areas exchange names started out as three letters at the start of a phone number, but in most places they were transitioned to two letters and 5 numbers, or 2L-5N in telcom parlance. Exchange names were in use in the US, Canada, Europe, and Australia, but we don't know about the rest of the world. Here's a few of the contributions that have added to the historical background.

Unique Exchange Names

I originally thought that for any two letter combination there must have been a unique exchange name. For example, GR would always be GReenwood. This proved to be a bad assumption when we found different exchange names which used the same two letter combination.

Unique Letter Combinations

I originally had a theory that for any two numbers on the dial, the same two letters would always be used for the exchange name. We quickly discovered that that was often not true, even in the same geographical area.

No Area Code Prefixes

Up until very recently, the first digit of a 7 digit phone number could not be 1 or a 0 so that long distance dialing and operator could be reliably identified. Similarly, the second digit could not be either 0 or 1 so that area codes could be identified. This changed sometime in the last ten years, and now phone numbers which have a 1 or 0 as the second number are common in some areas, especially for cell phones. I had assumed that this was also true during the period when exchange names were in use, but we discovered phone numbers with 0 as the second digit (this was a phone number which was not written using an exchange name however). We still haven't seen any that have a 1 as the second digit, or that start with a 1 or a 0.

Mapping Between Exchange Names and Central Offices

With the help of contributions to the project, it now seems that exchange names and central offices were closely linked. Originally, the central office name was also the exchange name, and the central office was often named for the town or street where it was located. Later, central offices started serving multiple exchanges. In many cases more than one central office in an area would use the same exchange name, but they would serve different exchanges. For example, one office might serve MUlberry-7, while another one served MUlberry-5.

Send Us Your EXchange Names

How do exchange names work?

Everybody used to know this 30 years ago, but many young whippersnappers have probably never heard of this:

An exchange name is a word that is used to represent the first two letters of a 7 digit telephone number (exchange names have nothing to do with area codes or country codes). The first two letters of the exchange name are the first two digits of the phone number, when they are spelled out on a telephone dial or keypad. So for example, the exchange name "SYcamore" means that the first two numbers of the telephone number are "79", and SYcamore-4-3317 would be 794-3317, (my friend's old phone number 30 years ago).

last modified: 1 November 2006

©2006 Robert Crowe. All Rights Reserved.