NetValley (original) (raw)

... a chronology of Telegraph,Telephone and Radiotelephone, the three services reaching across the Atlantic before the1960Echo satellite**.**

By Alan Leon Varney, AT&T Network Systems

TELEGRAPH

1837 - Charles Wheatstone patents "electric telegraph"
1844 - Samuel Morse demonstrates "Morse code" -- but this is the old version, where a number is assigned to each possible word. Alfred Vail helps him later with a "variable-length letter code".
1845 - General Oceanic telegraph Co. registered in NYC to link Europe and North America (was this just another stock swindle?)
1847 - Gutta-percha (an inelastic latex) is discovered. It serves as a reliable insulator in water (reliable, but not great capacitance).
1849 - England to France telegraph cable goes into service -- and fails after 8 days.
1850 - Morse patents "clicking" telegraph.
1851 - England-France commercial telegraph service begins. This one uses gutta-percha, and survives.
1858 - August 18 - First transatlantic telegraph messages via wire. Cyrus Field (a 35-year-old retired merchant) & John Pender formed a British company, "The Atlantic Telegraph Co." The cable deteriorated quickly, and failed after 3 weeks.
1861 - First USA transcontinental telegraph cable begins service.
1868 - First commercially successful transatlantic telegraph cable completed between UK and Canada, with land extension to USA.
(Lack of repeaters & cable capacitance in insulation restricted
the cable to 2 words/minute -- signaling speed was inversely
proportional to square of length, per Lord Kelvin's prediction.
A "siphon receiving" mechanism raised that rate to 20 WPM in 1870.
Even 2 WPM beat the next fastest method; 10 days by steamship.)
Also, Werner Siemens patents a keyboard perforator for Morse code.
1874 - Baudot invents a practical Time Division Multiplexing scheme or telegraph. Uses 5-bit codes & 6 time slots -- 90 bps max. rate. Both Western Union and Murray would use this as the basis of multiplex telegraph systems.
1875 - Typewriter invented.
1880 - Oliver Heaviside's analysis shows that a uniform addition of inductance into a cable would produce distortionless transmission.
(It would be 40 more years before Bell Labs devised a practical method
of producing uniform inductance -- "permalloy" magnetic ribbon spiral
winding around a conductor. This would permit 400 WPM on the
New York-Azores Western Union cable in 1925.)
1901 - Donald Murray links typewriter to high-speed multiplex system, later used by Western Union.[ The beginnings of Teletype ? ]

TELEPHONE

1876 - Bell patents telephone.
1877 - Bell attempts to use telephone over the Atlantic telegraph cable. The attempt fails.
1883 - Test calls placed over five miles of under-water cable.
1884 - San Francisco-Oakland gutta-percha cable begins telephone service.
1910 - Chesapeake Bay cable is first to use loading (inductor) coils underwater. Contained 17 pairs of 13-guage conductors.
1915 - USA transcontinental telephone service begins (NY-San Francisco).
(Used 2500 tons of 8 guage copper on 180,000 poles, with loading coils every 8 miles. Three vacuum tube repeaters were initially used -- by 1918, that was increased to 8 repeaters. In 1920, all loading was removed and 12 improved repeaters installed. This resulted in doubling of the bandwidth (to 3 kHz), halving of the loss and a 3.5-fold increase in propagation speed. The reduction in echo was very obvious.) (A 3-minute call was $20.70)
1921 - Key West-Havana cable begins service, using continuous loading via "permalloy" wrap and a blend of rubber and gutta-percha.
1928 - Design of a continuously-loaded Newfoundland-Ireland cable begins,
as a joint AT&T-British Post Office project. The planned loss was 165 dB over 1800 miles. It used 4 layers of Perminvar tape for loading. Manufacturing in Germany began in 1930. The Depression caused all work to be abandoned. By the late 1930s, submerged repeaters and multiplexing promised more circuits at the same cost.
1947 - Polyethylene replaces rubber & gutta-percha as preferred insulator.
1949 - "SB" submarine cable developed by AT&T, using polyethylene + 5% butyl rubber dielectric. The cable was made up of a core of several dozen steel wires, covered by a copper tube, then about .2 inches of dielectric and another copper tube, covered by a plastic jacket and armor.
1950 - Repeatered SB submarine cable used on Key West-Havana route.
1952 - Joint AT&T-BPO meetings at Dollis Hill lab to begin transatlantic cable project.
1953 - Canada (Canadian Overseas Telecommunications Corp.) joins in project,
along with Eastern Telephone & Telegraph Co. (AT&T's subsidiary in Canada).
1955 - June 28, HMTS "Monarch" leaves Clarenville, Newfoundland laying cable. After weathering Hurricane Ione, it reaches the Firth of Lorne in Oban, Scotland on September 26.
1956 - June 4, "Monarch" leaves Oban to lay the other cable (these are
uni-directional repeaters). Final splice at Clarenville, August 14. All links and channels were tested within 6 weeks. A total of 102 repeaters were needed on the main cables.

Connections at the North American end:
USA (29 circuits of the 35 originally available) White Plains, NY (via L1 coaxial cable) to Albany, NY or West Haven, Connecticut Albany/West Haven (via K-carrier) to Portland, Maine Portland (via TD-2 microwave) to Sydney Mines, Nova Scotia Sydney Mines (via BPO underwater cable) to Clarenville.
Canada (6 circuits) Montreal (via carrier on cable and open wire) to Saint John, New Brunswick
St. John (via TD-2 microwave) to Sydney Mines (as above).

Sept. 25, 1956 at 11 am EST, Chairman Craig of AT&T calls Dr. Charles Hill,
Her Majesty's Postmaster General. This initiates the first long-term transatlantic telephone service, using the TAT-1 cable. [In 1966, after ten years of service, the 1608 tubes in the repeaters had not suffered a single failure. In fact, more than 100 million tube hours over all AT&T undersea repeaters were without failure.]
1963 - First cable from New Jersey to England.
1965 - First cable from New Jersey to France.

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RADIOTELEPHONE (cable's competition)

1920s- Catalina Island telephone service to mainland via radio system.
Replaced by cable in 1923 so frequencies could be used for broadcast.
For 6 weeks, a "privacy" system was tested, using inverted sidebands
and a "wobbling" carrier. Later systems used 4 or 5 "bands",
re-ordered before transmission. Some bands were inverted.
The band arrangement was changed a few times per minute, in synch.
1921 - British "Marconi Co." offers 3 MHz calls between England and Norway.
1923 - Amateur radio proves that high frequency radio can reach long distances (sometimes). Transatlantic transmission demonstrated.
1927 - first commercial transatlantic radio telephone service begins.
This uses low frequency radio from RCA's Rocky Point, Long Island & Rugby, England transmitters. Receivers were in Houlton, Maine and Cupar, Scotland. The 2800 Hz bandwidth was modulated to 33 kHz carrier & then 92 kHz, with the lower sideband then at about 60 kHz. Three 250-watt tubes in parallel amplified this, and fed a 2-stage
water-cooled final stage of up to 35 tubes, yielding 150-200 kW. Low frequencies were considered more "reliable". HF radio took 30 dB losses over day-long periods between Deal, New Jersey and New Southgate, England during magnetic disturbances. On those
same days, LF radio actually gained a couple of dB. (A 3-minute call was $75.)
1929 - HF radio begins commercial transatlantic service (2 circuits!). Transmitters in Lawrenceville, New Jersey and Rugby, England; receivers in Netcong, New Jersey and Baldock, Hertfordshire. (Calls used which ever radio system was working "best" at the time. By1931, HF was the choice 80% of the time.)
1930 - HF radio service begins to Buenos Aires.
1931 - Dixon/Point Reyes, California radio begins transpacific service.
1932 - Florida sites begin Caribbean & Central American service.
1937 - USA can call 68 countries via HF radio -- 93% of the world's telephones are interconnected via wires & radio waves.