Teletypewriter Intercommunication Expands
_TELEX_
As a result of the acquisition of patents of the Morkrum-Kleinschmidt
Company by the Lorenz company, Siemens & Halske, and, later, the Creed
company in England, all of which we have discussed briefly,
teletypewriter intercommunicating expanded rapidly. In just a short
time, through the cooperation of these companies, it spread over all of
Europe and was named TELEX (_TEL_eprinter _EX_change Service).
Dr. Gerhard Grimsen of the Lorenz company, in a letter to Edward E.
Kleinschmidt, dated July 11, 1962, states, in part (slightly edited):
The story of printing telegraph apparatus using an equal length code
in the Lorenz Co. commences in 1927 with the acquisition of the most
important patents of the Morkrum-Kleinschmidt Co.
Before then, the Lorenz people were busy in manufacturing Morse
apparatus and delivering exchange tickers which used the Hughes code.
The transmitter had a piano keyboard, the receiver was a page printer
with a moving type wheel.... The biggest network of this kind was
installed in the Berlin Police service (with one transmitter and about
300 receivers). The connections between the headquarters and the
substations were built by using guttapercha cable lines owned by the
police administration. This broadcasting network was erected around
1907. By 1927 the cables had aged, by normal corrosion, to such a
degree that instead of 110-volt double current transmitting voltage,
little by little, up to 220 volts was necessary for a fairly
satisfying operation. Also, the maintenance of the apparatus became
more costly.
This was the situation when some communication experts of the police
and the post administration made the first studies about the newest
telegraph technique in the U. S. A.... They found that the start-stop,
five-unit tape printer, the Model 14, developed and manufactured by
the Morkrum-Kleinschmidt company, would be the best instrument to
replace the old ones in the police service as well as in the telegraph
business of the German post administration.
Of special importance to the police service was the fact that by
introducing this apparatus, it was not necessary to build a new
network because now it became possible to rent normal telephone lines
using single current, 40-milliampere, 60-volt current only.
Siemens and Halske engineers, in 1925, had designed a teleprinter using
the five-unit-code, start-stop principle. This was manufactured and
improvements added, including the new start-stop method developed by
Morkrum-Kleinschmidt. The Creed company, which had started manufacture
of start-stop teleprinters before 1930, having purchased several Morkrum
printers before the consolidation of that company with the Kleinschmidt
company, also designed a teleprinter for the new five-unit-code,
start-stop system.
In another write-up, Dr. Grimsen states that after the Siemens company
came into the picture, a fully automatic teleprinter network was started
in 1933 with a trial installation between Berlin and Hamburg for about
forty private subscribers. The results were so encouraging that the
German Reichspost continued the work, and five years later the TELEX
system contained about 10,000 subscribers.
TELEX service was introduced in Great Britain in 1932 and was worked
over the telephone network, using a single-tone voice frequency carrier
signal which was keyed on and off by the teleprinter transmitter. (From
Freebody’s _Telegraphy_.)[12]
Interconnection for TELEX service was made by dialing a subscriber as in
telephone operation. TELEX directories then, as now, gave the call
numbers of subscribers. Types of answerback devices were designed in
both England and Germany which finally developed into an arrangement
whereby the calling subscriber would, after dialing a number, press a
special key, the shifted D key—named the “Who-Are-You?” button—which
would cause the transmission of a signal code automatically to activate
the called teletypewriter mechanism into transmitting its TELEX number.
Further apparatus, a device to punch the code in a tape and a
punched-tape-controlled transmitter, was soon added.
The Siemens company also developed and built completely automatic
switching equipment for the TELEX system which is used by many telegraph
administrations.
Through the cooperation of the companies who were manufacturing
teleprinters and associated equipment, the many problems that appeared
were eventually solved to improve the apparatus and bring the TELEX
system to eventual perfection for worldwide telegraph communications.
(At the time of this writing, according to statistics, there are nearly
1,000,000 TELEX subscribers throughout the world.)
One of the problems faced in setting up such a worldwide system was that
of standardizing the code and operating speed. At the time of
Kleinschmidt’s stay in London in 1930 to close negotiations with Creed
for the sale of Morkrum-Kleinschmidt’s foreign rights, he met Mr. Martin
Feuerhahn of the German Telegraph Administration who at that time was in
conference with Creed and representatives from the British Telegraph
Administration as to standardizing on an alphabet and telegraph code for
international communications. Mr. Feuerhahn argued for the adoption of
the American Murray alphabet and code, stating that he already had the
approval and consent of the French, Italian, and Belgian telegraph
administrations.
Mr. Feuerhahn and Kleinschmidt spent some hours together. After their
return to their respective countries, Kleinschmidt received a letter
from Mr. Feuerhahn referring to their talks and stating that he had been
in correspondence with Mr. Benjamin of Western Union and Mr. Parker of
Bell Laboratories with regard to code and other pertinent matters of
standardization so that an International Teleprinter Exchange could be
extended into the United States. Another letter dated October 10, 1931,
reviewed the aforementioned standardization search.
The Murray alphabet and 7½-unit code were soon adopted and are still in
use today in TELEX.
In later years, an association, the Consultative Committee on
International Telegraph (CCIT—now the CCITT to include the telephone),
was formed and met regularly to discuss problems and to set operating
regulations for the TELEX apparatus in an intercommunicating system. The
CCITT at this writing is still meeting regularly on worldwide
standardization in both telegraph and telephone communications.
_TELEX IN THE UNITED STATES AND TWX_
In the United States, in November 1931, the Bell Telephone Companies
announced an intercommunicating teletypewriter service, called TWX for
short (_T_eletype_W_riter e_X_change), by which interconnections could
be made by a switchboard operator as in telephone service. One of their
first advertisements named it a “Telephone Typewriter Service, a service
that typewrites by wire, a method of inter-office communication that has
the quickness of the telephone, the flexibility of conversation, the
accuracy of the typewriter, the authority of the printed word, the
permanency of print.”[13] Tape-punching and tape-controlled transmitting
apparatus was provided. This service allowed subscribers to carry on a
typewritten conversation at a charge less than the cost of a telephone
call, whether to local or to distant areas. The maximum speed of this
equipment was limited to sixty words per minute.
[Illustration: Telephone Typewriter Service (early TWX apparatus)
_reproduced by permission of American telephone & Telegraph Co._]
There are approximately 54,000 subscribers to TWX at this writing, and
the TWX directory gets fatter with each new issue. In 1962 all TWX
machines were converted to direct dialing operation, making the service
easier to use. Instead of going through “Operator” by manually typing
out the call letters of the party being called, one now merely depresses
the Originate button, listens for the dial tone, and then dials the TWX
number of the party wanted.
RCA Communications, Inc., was the first to extend international TELEX
service to Bell System teletypewriter subscribers (1955), enabling them
to make and receive overseas calls on their domestic TWX machines.[14]
As stated, the TWX machines were geared for 60-words-per-minute
operation, whereas the TELEX system operated at 66 words per minute. It
was therefore necessary for R.C.A. to use conversion apparatus to an
error-detecting code for overseas radio transmission. This code was a
seven-unit code, using three marking and four spacing elements, giving
35 usable combinations. By using a special printer, when a faulty
combination was received, a special error symbol was printed.
Western Union, in May of 1958, introduced TELEX service between New York
City and various Canadian points. By 1962 the service had been extended
to 67 United States cities, and at this writing they expect to serve 180
United States cities with an anticipated subscriber capacity of many
thousands.[15]
In addition to domestic service between U. S. cities, subscribers can
dial automatic teleprinter connections to Canada and Mexico. Also, they
can obtain direct TELEX connections to other parts of the world through
the overseas facilities of RCAC (Radio Corporation of America
Communications), AC&R (American Cable and Radio), and WUI (Western Union
International). The operating speed of 66 words per minute and also the
teleprinter keyboard in the U. S. TELEX network conform to international
standards of the CCITT. This provides complete operating compatibility
with other TELEX systems throughout the world without the need for speed
and keyboard translators.[15]
SOME OF TODAY’S TELEX APPARATUS
[Illustration: The SAGEM Electronic Teleprinter used in TELEX
_Picture by courtesy of Société d’Applications Générales d’Electricité
et de Mécanique_]
[Illustration: Western Union TELEX
_Picture through courtesy of Western Union Telegraph Co._]
[Illustration: General Post Office TELEX Installation
_by courtesy of H. M. Postmaster-General_]
[Illustration: (uncaptioned)]
[Illustration: Standard Elektrik Lorenz TELEX Apparatus
_reproduced by permission of Standard Elektrik Lorenz_]
[Illustration: Siemens & Halske TELEX Apparatus
_Picture by courtesy of Siemens & Halske_]