AT&T Long Lines Technology and Equipment

Switching

• No. 5 Crossbar (a collection of articles from the Bell Laboratories Record,1949-1951; courtesy of Sam Etler)
• "The Evolution of Telephone Switching" (article from the Bell Laboratories Record, June 1965)
• Western Electric No. 4 Electronic Switching System
  introduced in 1976 and still the foundation of AT&T's switching network
• "Programming the Number 101 ESS" (article from the Bell Laboratories Record, Apr. 1965)
• "The 304 Conference Switching System" (article from the Bell Laboratories Record, Jan. 1965)
• "The Crossbar Switch" (article from the Bell Laboratories Record, July 1937)
• A New "B" Board for Panel Offices (article from the Bell Laboratories Record, December 1930)

Analog Frequency Division Multiplexing

• Multiplex hierarchy diagram

Frequency Control

• The Bell System Primary Frequency Standard
  advertisement from 1952

Microwave Radio

General Information

• "The TD2 Story", a three-part article from the Bell Laboratories Record:
  • Part 1 - "From Research to Field Trial" (October 1967)
  • Part 2 - "Vacuum Tubes and Systems Engineering" (November 1967)
  • Part 3 - "Changing for the Future" (December 1967)
• "TD2: Eighteen Years And Still Growing", from the Bell Laboratories Record, July-August 1968
• Booklet "Radio Relay: Communications by Microwave"
  Thanks to Al Hajny, P.E. for providing these scanned images.
• "Microwaves for Relaying TV Programs"
  From the November 1948 issue of "Radio and Television News"
• "The Microwave Era Begins"
  From the October 1950 issue of "Radio and Television News"

Transmitter-Receivers

• TD-2 Microwave Radio Transmitter-Receiver Bay Description
  Bell System Practice 410-410-100, Issue 1, March 1975
• List of microwave radios used in the Bell System
  from Bell System Practice 010-150-002, April 1968
• TD-2 radio bay, showing major components
  From: "TD-2 Radio Channel Maintenance", OJT 57, Issue 1, June 1971, AT&T Long Lines, p. 16
• TD-2 radios bays undergoing factory checkout
  Advertisement, circa 1953-1954
• TD-2 vacuum-tube transmit amplifier
  From: "TD-2 Radio Channel Maintenance", OJT 57, Issue 1, June 1971, AT&T Long Lines, p. 184
• "Microelectronics Replace Vacuum Tubes in the Microwave Network"
  from the Bell Laboratories Record, February 1983

Data Transmission

• "The 1A Radio Digital System Makes 'Data Under Voice' A Reality"
  from the Bell Laboratories Record, December 1973
• "1A Radio Digital Terminals Put 'Data Under Voice'"
  from the Bell Laboratories Record, May 1974

Alarm and Control

• Advertisement for alarm and control system, from 1952
• C-1 Alarm System indicator panel lamp assignments illustration from a Bell System Practice

Antenna Systems

Delay Lens Antennas

• The KS-5759 Delay Lens Antenna: Description
• Bell Telephone Laboratories drawing ES-877600, "TD 2 Radio KS-5759 L1 Delay Lens Antenna Assembly" (sheet 1 of 2 sheets) Location: T01
• Bell Telephone Laboratories drawing ES-882975, "TD 2 Radio KS-5759 L1 Delay Lens Antenna Bracing Assembly" (2 sheets) Location: T01
• Western Electric drawing ED-63953-70, "Toll Systems / TD-2 Radio / Waveguide Iris for KS-5759 Antenna" Location: T01

Horn-Reflector Antennas

• The KS-15676 Horn-Reflector Antenna: Description
• "Broadband Horn Reflector Antenna" (article from the Bell Laboratories Record, Nov. 1955)
• Drawing of original horn-reflector concept, for U.S. patent application

Systems Combining Networks

• "A Microwave Systems Combining Network" (from the March 1963 Bell Laboratories Record)

Waveguide

• Western Electric Waveguide Products brochure (December 1967)

Towers

• Mark Foster's AT&T tower page
  Lists AT&T's tower type designations, with example photographs
• Western Electric Type "E" tower brochure (November 1967)
• Western Electric Microwave Tower Services brochure (March 1963)
• The concrete microwave towers
• TV Towers Sprout from Sliding Form (from Popular Science magazine, June 1950)

Coaxial Cable

• "Stevens Point and Minneapolis Linked by Coaxial System"
  article from the Bell Laboratories Record, January 1942
• 20-tube coaxial cable description
• 20-tube coaxial cable diagram, showing order-wire assignments
• Cross-section image of 20-tube coaxial cable
• Advertisement: 4000-Mile Trench
• Photo of coaxial-cable splicing training, from 1970s
• Close-up photo of coaxial-cable splice
• "New York - Chicago L3 System"
  article from the Bell Laboratories Record, May 1954
• Bell Laboratories Record, July/August 1967
  entire issue devoted to the L4 coaxial system

Alarm, Control, Testing and Monitoring

The L4 Remote Control Center

• Photo 1
• Photo 2

Maintenance, Repairs and Emergency Restoration

• Richmond, VA "Flying Squad"
• Photo of submarine coaxial cable repair, from 1973
• AT&T Job Aid 26, "Basic Coaxial Cable Maintenance", Issue 1, 1989 (on file)
• Restoration after bombings of microwave and cable stations in Utah and Nevada in 1961 (by David Massey)

Communications Satellites

• Booklet "The Telstar Experiment: The Bell System's Role in Communications Satellite Development" [copy on file]
• Angular Calibration Using Celestial Radio Sources" (from the January 1965 Bell Laboratories Record)

The Testboard

• A Private Line Testboard
• The Switched Access Remote Test System (SARTS)
• Carrier Transmission Maintenance System (CTMS) logo

The Power Room

• Gould PAT/PCT Data Sheet
  describes a typical "submarine cell" used in Long Lines station batteries

Wire-Pair (non-coaxial) Carrier Systems

• Advertisement for open-wire carrier system, from 1952
• Map of K-carrier route in Pennsylvania, from 1937
• Catalog description of C-carrier equipment, from 1948
• J-Carrier twelve one-way voice circuits multiplexed on a single open-wire pair

Local Loop (Exchange) Plant

• "Dedicated Outside Plant" (from the January 1965 Bell Laboratories Record)

Related Technologies

• Teletypewriters - by Vaux Electronics
  Teletypewriters were used in the Bell System both for internal communications and for text communications services offered to subscribers, and for many years AT&T owned the Teletype Corporation, a major manufacturer of this equipment.

Support Systems

• Electric Incinerating Toilet - used at many stations in isolated areas.
• Rack for storing spare fluorescent lamps - everything had its place in the Bell System.
• Bell System waterless hand cleaner - for hard-working Telephone hands.
• Bell System floor finish - helping AT&T keep those floors looking great.

Mobile Communications

• "Telephones Aboard the 'Metroliner'", from the Bell Laboratories Record, March 1969

The Picturephone

• Bell Laboratories Record Picturephone issue, May-June 1969
  Adobe PDF file, 8.9 MB Courtesy of David Massey

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