931 14th St.
Colorado, Denver, and Phones
In 1876, the Colorado Territory was granted statehood, becoming the 38th state of the Union. In an unrelated development, but one that would rapidly become integral to the development of Colorado, the first long distance conversation took place that same year between Boston and Cambridge, Massachusetts, a distance of two miles. Despite its limited range, the telephone was rapidly becoming a popular means of communication, and advances in the technology would soon redefine “long distance.”
But we’re getting ahead of ourselves.
Two years later (in 1878), Frederick O. Vaille obtained rights from Bell Telephone of Boston to develop telephone service in the new Rocky Mountain state. The next year, Denver’s first telephone exchange opened at 1514 Larimer Street above Frick’s Shoe Store on the south side of Larimer Street. It housed the 17th telephone exchange in the nation. The office belonged to the Colorado Telephone Company. Three rooms contained a business office, battery room, and the central office where boy telephone operators connected the local subscribers’ calls. At the time, there were 162 subscribers. The telephone company also distributed its first telephone directory, using two different lists: one in alphabetical order by subscriber name and one classified by business type.
In 1880, the Colorado Telephone Company bought out the Western Union Company and moved its headquarters into the Western Union office located on the Bardwell Block of Larimer Street. Three months later in the year, the phone company moved again, just one block away to the new Tabor Block (formerly known as the Nassau Block) on Larimer Street. The company also discovered that young ladies made better operators than boys—they were more polite to customers (see sidebar in Building Tour–Odd Floors).
By 1884, Denver’s phone service had grown more than fourfold to 752 subscribers, and the central office completed almost 5,000 calls each day. The company moved into its new “fireproof” building at 1447 Lawrence Street in 1890. And in 1903 it moved to 1421 Champa Street.
Also in 1911, long distance finally lengthened its reach from New York to Denver, and by the following year San Francisco. A caller could talk to friends thousands of miles away as well as to the person next door, and many people took advantage of this service.
By the 1920s, Denver’s central office was overloaded and costly, and the Bell System decided to offer dial service in Denver (see our “Operators and Undertakers” heading in How Phones Work for more on dial service). This would automate most of the local calls and require fewer operators to make connections. It also sped up the whole process and cost less to operate on a daily basis. The catch: the switches for the new service would take up quite a bit of room and weighed over 2,000 tons. (Click here
931 Exhibit
Switching Example
How did the switches in the telephone building work? Play the video below to find out!
So what's going on in the video? The caller (left) lifts the handset to establish the circuit, then dials the digits of the telephone number. The dial sends a series of pulses, or clicks, down the circuit to the switch: one pulse for the number "1," three pulses for the number "3," and so on.
The Central Office switch contains banks of 10-level relays, each representing one of the numbers in a telephone number.
Each pulse from the caller's telephone advances a relay bank by one step. In this demonstration, the caller is dialing 341-5555, so the dial sends three pulses, then four pulses, then one pulse, and so on. The combination of connections establishes the path upon which the call goes through, and the called phone rings (right).
So the Bell System decided to build a new central office to house the new dialing equipment and to act as headquarters for the entire Mountain States territory (see map). When completed, the building housed enough equipment to serve half the city’s phones. (Click here
931 Exhibit
How to Use the New Dial Telephone
The new switching equipment in the 931 Building ushered in the age of the dial telephone to Denver—but this was very different from the old, "operator-driven" phones, and the phone company had to teach the public how to use the new system. Following are images from phone directories, signs, and even a booklet put out for this purpose. Click on the images to enlarge them. (All images are from the THG archives.)
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Instruction page from the phone directory on how to use the dial telephone. |
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The second page of the same instructions. |
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The 1429 Champa (old headquarters) window. The sign offers training classes. |
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This and the following images are pages from an instruction booklet given out by the phone company. |
|
The next pages of the booklet. |
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The next pages of the booklet. |
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The next pages of the booklet. |
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The next pages of the booklet. |
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The next pages of the booklet. |
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The next pages of the booklet. |
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The next pages of the booklet. |
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The next pages of the booklet. |
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The back cover of the booklet. |
(Use the links below to continue exploring this exhibit, or click here to continue a Guided Tour.)
Exhibit Entry | Site History | Local Com History | Architecture | True Murals | Building Tour Smoke Signals | Pony Express | Trains & Telegraphs | Colorado, Denver, & Phones
931 14th St.
Colorado, Denver, and Phones
Denver Central office on Champa St., around the corner from the site of the new building. (THG archives)
In 1876, the Colorado Territory was granted statehood, becoming the 38th state of the Union. In an unrelated development, but one that would rapidly become integral to the development of Colorado, the first long distance conversation took place that same year between Boston and Cambridge, Massachusetts, a distance of two miles. Despite its limited range, the telephone was rapidly becoming a popular means of communication, and advances in the technology would soon redefine “long distance.”
But we’re getting ahead of ourselves.
Two years later (in 1878), Frederick O. Vaille obtained rights from Bell Telephone of Boston to develop telephone service in the new Rocky Mountain state. The next year, Denver’s first telephone exchange opened at 1514 Larimer Street above Frick’s Shoe Store on the south side of Larimer Street. It housed the 17th telephone exchange in the nation. The office belonged to the Colorado Telephone Company. Three rooms contained a business office, battery room, and the central office where boy telephone operators connected the local subscribers’ calls. At the time, there were 162 subscribers. The telephone company also distributed its first telephone directory, using two different lists: one in alphabetical order by subscriber name and one classified by business type.
In 1880, the Colorado Telephone Company bought out the Western Union Company and moved its headquarters into the Western Union office located on the Bardwell Block of Larimer Street. Three months later in the year, the phone company moved again, just one block away to the new Tabor Block (formerly known as the Nassau Block) on Larimer Street. The company also discovered that young ladies made better operators than boys—they were more polite to customers (see sidebar in Building Tour–Odd Floors).
By 1884, Denver’s phone service had grown more than fourfold to 752 subscribers, and the central office completed almost 5,000 calls each day. The company moved into its new “fireproof” building at 1447 Lawrence Street in 1890. And in 1903 it moved to 1421 Champa Street.
Regional map. In 1929, MST&T also served the El Paso, Texas area and Ciudad Juarez, Chihuahua in Mexico. (THG archives)
In 1911, the Colorado Telephone Company merged with the Tri-State Telephone and Telegraph Company, and the newly merged company purchased the Rocky Mountain Bell Company to become the Mountain States Telephone and Telegraph Company (later known as Mountain Bell).
Also in 1911, long distance finally lengthened its reach from New York to Denver, and by the following year San Francisco. A caller could talk to friends thousands of miles away as well as to the person next door, and many people took advantage of this service.
By the 1920s, Denver’s central office was overloaded and costly, and the Bell System decided to offer dial service in Denver (see our “Operators and Undertakers” heading in How Phones Work for more on dial service). This would automate most of the local calls and require fewer operators to make connections. It also sped up the whole process and cost less to operate on a daily basis. The catch: the switches for the new service would take up quite a bit of room and weighed over 2,000 tons. (Click here
931 Exhibit
Switching Example
How did the switches in the telephone building work? Play the video below to find out!
So what's going on in the video? The caller (left) lifts the handset to establish the circuit, then dials the digits of the telephone number. The dial sends a series of pulses, or clicks, down the circuit to the switch: one pulse for the number "1," three pulses for the number "3," and so on.
The Central Office switch contains banks of 10-level relays, each representing one of the numbers in a telephone number.
Each pulse from the caller's telephone advances a relay bank by one step. In this demonstration, the caller is dialing 341-5555, so the dial sends three pulses, then four pulses, then one pulse, and so on. The combination of connections establishes the path upon which the call goes through, and the called phone rings (right).
So the Bell System decided to build a new central office to house the new dialing equipment and to act as headquarters for the entire Mountain States territory (see map). When completed, the building housed enough equipment to serve half the city’s phones. (Click here
931 Exhibit
How to Use the New Dial Telephone
The new switching equipment in the 931 Building ushered in the age of the dial telephone to Denver—but this was very different from the old, "operator-driven" phones, and the phone company had to teach the public how to use the new system. Following are images from phone directories, signs, and even a booklet put out for this purpose. Click on the images to enlarge them. (All images are from the THG archives.)
|
|
Instruction page from the phone directory on how to use the dial telephone. |
|
|
The second page of the same instructions. |
|
|
The 1429 Champa (old headquarters) window. The sign offers training classes. |
|
|
This and the following images are pages from an instruction booklet given out by the phone company. |
|
|
The next pages of the booklet. |
|
|
The next pages of the booklet. |
|
|
The next pages of the booklet. |
|
|
The next pages of the booklet. |
|
|
The next pages of the booklet. |
|
|
The next pages of the booklet. |
|
|
The next pages of the booklet. |
|
|
The next pages of the booklet. |
|
|
The back cover of the booklet. |
(Use the links below to continue exploring this exhibit, or click here to continue a Guided Tour.)
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Exhibit Entry | Site History | Local Com History | Architecture | True Murals | Building Tour
Smoke Signals | Pony Express | Trains & Telegraphs | Colorado, Denver, & Phones