History of AT&T Long Lines
Source: Hacker News
AT&T Long Lines – Long Distance Made Possible For The Masses
Source: Garrett Fuller, “AT&T Long Lines, A Forgotten Tale” (with minor corrections and additional notes from Telephone World).
Overview
The Long Lines division of AT&T was the “long‑distance” arm that linked the regional Bell companies and independent telephone operators. It formed the backbone of the nation’s telephone infrastructure from the early days of the service until the 1984 AT&T divestiture. After the breakup, Long Lines remained AT&T’s core network until Southwestern Bell acquired it in 2005, creating the “new” AT&T we know today.
AT&T Long Lines – Long Distance Made Possible For The Masses
The period from the 1950s through the 1980s can be called the golden age of telecommunications. While computers shrank from room‑sized machines to desktop units, television moved from a luxury to a household staple, and telephone service expanded beyond voice to near‑instant data transfer.
The AT&T Long Lines system was a key driver of that transformation. By avoiding the vulnerable, expensive, and high‑maintenance wired networks of the era—long before satellite links and fiber optics—Long Lines let people communicate across the country with unprecedented reliability.
The History of the Long Lines System
During the early days of telegraph and telephone service, coaxial‑cable “long lines” were the only option for intercity connections. These wired links suffered two major drawbacks:
- Vulnerability – Like power lines, they could be knocked down by trees, storms, or accidents, causing outages that could affect hundreds of thousands of customers.
- Cost & Maintenance – Installing and repairing miles of thick cable was expensive and labor‑intensive, especially before automated fault‑location systems existed.
AT&T, as part of the Bell System, introduced a smarter solution: a network of microwave relay towers.
- First coast‑to‑coast automated call – On August 17 , 1951, the first Direct Distance Dial (DDD) call was placed using the microwave system that would become known as the “Skyway” or “Telephone Skyway.”
- Rapid expansion – From that initial launch, the network grew both in geographic reach and in the types of traffic it carried. In addition to voice, Long Lines transmitted television programming, military communications, and later computer data via teleprocessing systems and modems.
Each tower housed a line‑of‑sight horn antenna that transmitted and received microwave signals. A call originated in one part of the country would hop from one relay site to the next until it reached the station nearest the destination, where it would be handed off to the local copper network and delivered to the subscriber’s telephone.
The same microwave links carried television signals, enabling networks such as NBC and CBS to distribute live and pre‑recorded shows nationwide. The first live television relay, for example, carried Edward R. Murrow’s See It Now in 1951.
Designed to Last
During the height of the Cold War, the strategic importance of Long Lines grew dramatically. Many towers featured:
- Underground base stations – Shielded rooms built to survive the electromagnetic pulse (EMP) from a nuclear blast, equipped with survival kits similar to those found in fallout shelters.
- Robust above‑ground structures – Horn antennas and tower superstructures engineered to remain operational after a nuclear detonation.
- Western Electric equipment – All transmission gear, antennas, towers, and diesel backup generators were manufactured by Western Electric, the same company that collaborated with IBM on the SAGE air‑defense system.
IBM even used the Long Lines network for confidential communications in Kingston, New York.
New Discoveries and Post‑Monopoly Decline
In the 1970s, emerging technologies began to eclipse microwave relay:
- Fiber optics – Underground fiber‑optic cables offered vastly higher bandwidth, lower attenuation, and immunity to weather‑related damage.
- Satellite communications – Geostationary satellites provided global reach without the need for line‑of‑sight towers.
These innovations, combined with the deregulation of the telephone industry after the 1984 AT&T divestiture, led to the gradual retirement of the Long Lines microwave network.
The Long Lines system may be largely forgotten today, but its legacy lives on in the modern, high‑speed communications infrastructure that connects us all.
Cleaned‑up Markdown
The early coaxial‑based cable systems were soon eclipsed by two major innovations.
Fiber‑Optic Transmission
Fiber optics were far faster than coaxial cable because they use light to transmit data through strands of transparent material that act as waveguides.
Satellite Relays
Television programs could be relayed via satellites orbiting in the upper atmosphere. This allowed near‑instantaneous, wide‑area distribution with minimal ground equipment—far less vulnerable to storms or vandalism than the rural microwave towers scattered across places like Missouri.
These advances arrived just as AT&T (the Bell System) was feeling the pressure of antitrust actions. The Department of Justice was eager to break up the massive monopoly that let the company charge whatever it wanted for telephone service.
Key points about the Bell System
- Also known as “Ma Bell.”
- Operated a nationwide monopoly, inflating prices for telephone service.
- In 1984, the DOJ forced a breakup, creating dozens of smaller companies nicknamed “Baby Bells” (e.g., Southwestern Bell, Bell Atlantic).
- Those Baby Bells eventually evolved into today’s major telecoms such as Verizon, CenturyLink, and the modern AT&T.
After the breakup, the new, smaller carriers adopted fiber‑optic and satellite technologies, quickly rendering the Long Lines system obsolete.
By the early 1990s, AT&T—now facing fierce competition—decided the Long Lines network had run its course. The once‑state‑of‑the‑art infrastructure was abandoned, leaving behind towers and buildings that serve as relics of a forgotten chapter in telecommunications history.
The Impact of the Long Lines System
Post‑breakup AT&T did not stay small for long. It rebounded to become one of the “big three” wireless carriers, rebuilding towers across the nation (including many rural areas).
This Long Lines center, located on the roof of a present‑day AT&T office, shows how the towers still stand despite being out of use for decades.
— Photo: Spencer Harding
What the towers represent
- Historical reminder: From party lines and operators (“Betty, can you connect me to Mr. Smith?”) to today’s handheld phone‑computer hybrids, the towers mark how far we’ve come.
- Cold‑War legacy: Like old aircraft, missile silos, or the SAGE system, Long Lines was part of the first line of defense during a period of constant geopolitical threat.
Current state of the towers
- Abandoned: Many towers (e.g., the Slater station) have sat idle since the early 1990s. Their bases are overgrown, horn antennas are weathered or removed, and some platforms are left with only the mounting holes.
- Repurposed: After AT&T sold many antennas in the late 1990s, several towers found new life:
- Converted to ham‑radio stations, using the tower as a giant antenna.
- Leased to cell‑phone carriers (AT&T, Verizon, etc.)—often owned by companies like American Tower—and fitted with modern cellular equipment.
For More Information
Lists of AT&T Tandems
| List | Time period | Description | Link |
|---|---|---|---|
| Historical 4A/4M Crossbar Tandem List | 1940s – 1970s | Catalog of the original 4A/4M cross‑bar tandems that formed AT&T’s long‑distance backbone in the mid‑20th century. | View list |
| List of 4ESS/N4E Tandems | Modern era | Current AT&T long‑distance tandem network, covering both 4ESS (Electronic Switching System) and the newer N4E (Next‑Generation 4ESS) tandems. | View list |
Both links point to the Telephone World site, which maintains up‑to‑date reference tables for AT&T’s tandem switching equipment.