PRINTING TELEGRAPHY ...
A NEW ERA BEGINS
[Illustration: Autograph, Edward E. Kleinschmidt—1967]
_Edward E. Kleinschmidt
1967_
PREFACE
Having been associated with the printing telegraph for more than sixty
years, I have felt the urge to write a résumé of the problems and the
progress made during my time toward today’s wonderful achievements in
the art of telegraphic communications.
It is interesting to note that of all the old-time electric telegraph
systems, it appears that only those using the Morse dot-dash code
invented in 1837 and the permutation code devised by Gauss and Weber in
1833 (now known everywhere as the Baudot code) have survived today.
Samuel Morse’s code, which was modified somewhat in several letter code
compositions to facilitate its use anywhere in the world, has become an
audible, easily learned international language, loved by its users
everywhere. It will no doubt continue to be used for some time to come,
as long as we have our railroad telegraph operators, radio amateurs,
police CW systems, certain branches of the Armed Forces, and any others
who converse in dits and dahs.
The permutation code has taken hold firmly, too. Its use of five pulses
transmitted in varying combinations of on and off, or positive and
negative, conditions has wide application in today’s printed
communications systems. As in the Morse system, alphabets for the
five-unit permutation code system have been modified as to letter code
compositions for international correspondence. The permutation code uses
the powers of two in progressively selecting a letter printing position.
The binary code uses the same selective stops by yes or no designation
in a system of counting by the powers of two. It is used where larger
groups of yes or no positions are required, as in data processing and
computer systems.
This writing, then, is a bit of history that will put together the
constructive developments that brought about the present era of the
worldwide, telegraphically-transmitted printed word.
I wish to acknowledge with great appreciation the informative material
sent to me by my friends, both here and in foreign lands, who are
associated with the telegraph industry.
For assembling information we have gathered from various sources and for
the most helpful assistance given me in writing this story, I also want
to thank my secretary, Mrs. Doris Pompilio.
Edward E. Kleinschmidt
PRINTING TELEGRAPHY ...
A NEW ERA BEGINS
CHAPTER 1
Introduction
It is a major effort today to keep pace with the rapid advances in the
field of printed communications. Hardly a day passes that we do not read
of a new development in equipment that is more complex, farther
reaching, more rapid in operation....
This electrical, or electronic, transmission and interchange of the
printed word might be said to be an evolvement of the old printing
telegraph systems. Such systems, over the years, while not so rapidly as
today, were also improved upon, modified, speeded up, but could be used
only in the point-to-point transmission of messages.
While the railroads had been using the Morse code system (key and
sounder) satisfactorily, they would have preferred a system whereby a
printed record could be obtained. In the industrial world, too, there
was need for a businessman’s printing telegraph—a means to type out
messages, directly and interchangeably, to far-off associates. And there
was always that dream, starting with the earliest telegraph
experimenters, of being able to correspond instantly with one another
anywhere in the world. Indeed, the need for all this had been known for
many years, but not the way.
It was after the turn of the century that telegraph engineers began in
earnest to think about a system of telegraphy that would permit direct
intercommunication by the printed word, and direct circuit connection to
any outlying subscriber as in the telephone communication system.
Up until then, apparatus for transmitting telegrams, such as that of
Wheatstone & Cooke, Morse, Hughes, Barclay, etc., also the step-by-step
stock tickers and bulletin printers, used various types of
code-signaling devices in which the code varied in length as to the
transmission of more frequent or less frequent letters.
Now in order to provide a practical telegraph system permitting the
interconnection of apparatus throughout the world, the first basic
requisite is a standard signaling code; this code, moreover, must be of
such nature as to use the simplest form of electrical signaling (such as
make and break signals, or positive and negative signals), and the code
should be of equal length for all characters.
The permutation code, where combinations of five plus and minus pulses
will give thirty-two selective positions, was suggested as far back as
1833 by Gauss and Weber. Whitehouse, in 1854, and Barnett, in 1860,
experimented further, using the permutation code to operate a recording
mechanism. However, no practical means for actually printing letters and
figures was found until 1882 when Jean Maurice Emile Baudot designed a
multiplex system to permit the transmission of four messages in each
direction over a single line circuit. Later, Baudot designed a tape
printer in which the selecting and printing mechanisms comprised an
ingenious arrangement of cooperating parts, including a rotating
typewheel associated with a coded combiner wheel and five stationary
elements selectively movable to received code positions, each element
having an extending finger to be brought into contact with the periphery
of the coded combiner wheel upon the completion of a selective code
setting. When the code combination of the set fingers matched a code on
the wheel, a print roller was released to press the recording tape
against the typewheel and print the selected letter.
Although the Baudot Multiplex was used extensively in Europe, engineers
and inventors in the United States had not produced a practical 5-unit
permutation-code teleprinter system. They were constantly searching for
a unit code system requiring a minimum number of electrical impulses to
operate a telegraph printer. Various types of relay systems using
distinctive signal pulses were proposed. A three-unit-code system that
showed promise, and did not require synchronism, used four different
electrical pulse conditions: a high voltage positive or negative pulse,
and a low voltage positive or negative pulse. Records show that many
inventors played with this code and that John Burry, C. L. Krum, G. A.
Cardwell, and J. C. Barclay, among others, built operable equipment
using such a code arrangement. The following excerpt from Cardwell’s
patent No. 905,497 of December 1, 1908, may be of interest. It describes
the code arrangement of four different line conditions in three signal
groups to produce 36 different code combinations.
In order to energize the controller magnets in proper sequence to
position the type wheel for printing a desired letter, a predetermined
code or system of sending in the impulses is essential. In an
instrument constructed by me in accordance with the present invention
I have used the following:
1-2-1 letter space
1-2-3 carriage return
1-2-4 line space
1-3-1 type wheel shift
1-3-2 type wheel release
1-3-4 A
1-4-1 I
1-4-2 O
1-4-3 D
2-1-2 E
2-1-3 H
2-1-4 N
2-3-1 W
2-3-2 R
2-3-4 S
2-4-1 T
2-4-2 V
2-4-3 U
3-1-2 -
3-1-3 ,
3-1-4 ?
3-2-1 Y
3-2-3 C
3-2-4 F
3-4-1 G
3-4-2 Q
3-4-3 L
4-1-2 M
4-1-3 J
4-1-4 B
4-2-1 X
4-2-3 Z
4-2-4 .
4-3-1 K
4-3-2 P
4-3-4
The numerals in the above code or system indicate the sequence of the
impulses through the relay contacts 1, 2, 3 and 4.
Cardwell’s backers formed the American Telegraph Typewriter Company and
sold shares, claiming a great profitable future for their apparatus. A
few printers were built, but, on extended service tests, the
high-low-voltage feature proved to be impractical and the company
folded.
J. C. Barclay of the Western Union Telegraph Company designed printing
apparatus and perforated tape transmitting equipment for this type of
system, but, after limited use of the high-low-voltage principle, he
changed this feature to long and short pulses with discriminating
relays. With later improvements, this system was put into service on a
number of Western Union message circuits.
_Note:_ Today, in the 1960s, the techniques of frequency division and
electronics could be used for transmitting three different line
conditions from a group of four different frequencies. In such a
system, synchronism between send and receive terminals, or the
start-stop method to control correct timing, is not needed. The
transmission of any selected group of three, when received in
succession at a teleprinter, will cause printing of a letter when the
third receiving relay completes a circuit to the selected printing
magnet. Transistor circuits with associated control elements could
replace the relays.
Telegraph companies in the United States were mostly using the Morse and
increased its efficiency through development of quadruplex operation and
high-speed transmission systems. However, the quest for a more efficient
printing telegraph system persisted and various types were proposed and
tried. All made use of codes that were impractical for
intercommunicating systems and, while some were used in message service
by the telegraph companies, they did not appear to have any great
advantage over the Morse telegraph.
In 1911, Western Union began investigating systems used in Europe. The
first to be tested was the Creed, a system for transmitting and printing
Continental or Morse code signals at high speed. After observing several
other systems, the Murray Multiplex, an improved and modernized version
of the Baudot Multiplex, was found to show better operating features
and, due to the use of the five-unit permutation code, more efficient
use of telegraph lines.
By agreement with Donald Murray, and with his cooperation, the so-called
Western Union Multiplex was developed, using Murray’s phonic wheel drive
and synchronous correction. Western Union engineers designed tape
transmitters and an autocontrol device for transmitting service signals.
A keyboard-operated, five-unit-code, tape punch was supplied by the
Morkrum Company. A page printer, which was later converted to print on
gummed tape, was supplied by the Kleinschmidt Electric Company. The
Western Union Multiplex was effective in increasing operating efficiency
and came into extensive use throughout the system.
From that time on, development of the Baudot permutation-code printing
telegraph apparatus was furthered by various companies, such as Bell
Laboratories, Western Electric, the Morkrum Company, the Kleinschmidt
Electric Company, as well as the companies of J. E. Wright, L. M. Potts,
and others.
It appears that all of these inventors experimented with the idea of
operating all transmitting and receiving apparatus at identical speeds
to transmit a five-unit-code combination by first transmitting a pulse
to start both transmitter and the distant receiver at the same time.
Synchronous operation was obtained by electric motors equipped with
governors to maintain correct speed; some used tuning-fork-controlled
impulse motors. A system of five relays with progressive contact
arrangements to cause cascade operation was also used to provide correct
timing. Later, when correctly-timed, 60-cycle alternating current became
available (see page 27), synchronous motors did the job.
Teleprinter apparatus using this synchronous method worked very well for
point-to-point transmission as was used by the telegraph companies and
news-distributing organizations to carry local traffic. It did not,
however, solve the sought-for plan for a teleprinter intercommunicating
system. When attempts were made to connect printers at different distant
points in a telegraph intercommunicating circuit while using the
synchronous principle, false reception and printing errors would occur,
due to variation in line circuit conditions and to a variation of the
mechanical start operation at outlying teleprinters. This required
frequent overline adjustment to keep the connected apparatus in phase.
The following is an excerpt from a patent application of Dr. Louis M.
Potts (later to become research engineer for the Morkrum-Kleinschmidt
Corporation), filed June 17, 1909, giving his idea for achieving a
teleprinter intercommunicating system on the synchronous principle. Dr.
Potts was a very capable telegraph engineer. His early association was
with the telegraph system of the Rowland Telegraphic Company which had
limited use in the early 1900s.
In those synchronous telegraph systems wherein the sending and the
receiving commutator brushes constantly rotate, it is necessary to
adjust these brushes so that they will approximately simultaneously
engage corresponding segments. To effect this adjustment there is
usually provided a special device embodying an additional segment on
each commutator, and the adjustment consists in causing the brushes to
arrive approximately simultaneously on this segment at the two ends of
the line. Such adjustment is known as “finding the letter” and has to
be made every time synchronism has been interrupted. According to the
present invention, the necessity of providing additional means for
performing the so-called operation of “finding the letter” is rendered
unnecessary, since the transmitting and receiving commutator brushes
at the two ends of the line start up afresh as it were for each
signal.
In a later patent application, filed October 11, 1913, Dr. Potts stated:
This machine has also the advantage of being able to operate with a
very short code. In order to adapt it to Morse circuits, it should be
capable of operating with a code at least as short as the Morse code.
In the present machine, I preferably employ a five unit code which,
together with the starting impulse and the lag between signals, is
actually shorter than the Morse code. Counting the five code impulse
periods, the starting impulse period and the period of lag between
impulses, each signal in my case, may be considered in comparison with
the Morse code as being seven units long, whereas the Morse code is
8.5 units long. The average signal being shorter than the Morse, the
delicacy of adjustment will be less and the distance of operation
greater than a Morse telegraph for the same rate of transmission in
words per minute.
Dr. Potts, however, still depended on like synchronous operation at both
terminals, and dual start, so he did not have the answer after all!
John E. Wright, who in the 1890s designed and built step-by-step
printing apparatus, including the Wright-Negron bulletin printer, also
turned his thoughts toward the five-unit permutation code for printer
operation and built several variations using the synchronous principle.
The Superintendent of Telegraphs for the Delaware, Lackawanna and
Western Railroad thought well of Wright’s apparatus and placed some in
operation. But, here again, reliable operation could be maintained only
in point-to-point operation. As will be noted in Chapter 2, Mr. Wright’s
patents were purchased by the Kleinschmidt Electric Company in 1922.
A paper issued by Siemens-Halske of Germany in January of 1917[1] states
that the Siemens Pendel Telegraph “is among the forerunners of the
eventual worldwide start-stop system for intercommunication by the
printed word.” The following excerpt translated from that description
briefly explains the operation:
The Pendel Telegraph uses the five-unit permutation code to select
characters, and operates on a start-stop principle. It is intended for
station-to-station, one-way operation, the line current normally being
closed to the positive side of the line battery. Transmission is under
control of a keyboard with keys arranged as in a typewriter. Upon the
depression of a key, the line battery is reversed, thereby
transmitting a negative pulse to line which effects the start of both
transmitter and receiver at the same time. Thereafter,
five-code-combination pulses are transmitted, followed by positive
current to line, thus restoring the circuit system to a normally
closed line condition.
The name “Pendel Telegraph” would make one think that the timing of
the transmitter and receiver were under control of a swinging
pendulum. This is not the case. However, it does have a plan for
simulating the action of a pendulum by an arrangement of springs and
semi-rotating weights to effect synchronism for each printing cycle;
and energy is derived from a motor which intermittently winds a power
mainspring to an even tension. This arrangement is started in
operation at both terminals at the same time and provides isochronal
motion at both transmitter and receiver for each transmitted
character. Due to multiple operations of the springs and weights used
to provide synchronous action, the operating speed is limited to four
or five letters per second.
In England, too, there was work being done along these same lines. Mr.
H. H. Harrison, who is so well known for his contributions over the
years in the telegraph field, devised printer apparatus using the
five-unit code which is described in Herbert’s _Telegraphy_,[2] as
follows:
The instrument is provided with a Baudot 5-key keyboard, and has a
step-by-step distributor which is mounted inside the casing. The
standard Baudot alphabet is used, but each letter or character is
prefixed by a positive starting impulse. Every time a key is depressed
a universal bar is actuated which closes contacts giving the starting
impulse and the distributors at both ends of the line step through six
spaces. The combiner is of the electrical type invented by Baudot, and
is similar to that used in Siemens’ new automatic printing telegraph.
Five relays of the class used for telephone purposes are set at the
receiving end, according to whether some of the stepping impulses are
positive or negative. The distributor is a trunk hunting switch as
used in automatic telephony, and consists of a ratchet wheel and
stepping electromagnet. On the shaft of the ratchet wheel is fixed a
wiper which sweeps over a semi-circular bank of contacts in response
to the stepping impulses. Two-way working is secured by means of the
differential balance.
(The article ends with the statement that a typewriter keyboard is
being constructed to replace the five keys.)
It appears that all of these telegraph engineers and inventors
envisioned a start-stop system and experimented with the idea of
operating all transmitting and receiving apparatus at identical speeds
by inserting a start signal before each group of letter code signals, to
start both transmitter and distant receiver at the same time, and a stop
condition between code groups.
In the following chapters will be shown the contributions made by both
the Kleinschmidt and the Morkrum companies in the printing telegraph
field, and finally their joint efforts which were to lead up to the
establishment of that now worldwide intercommunicating system, the
TELEX.