US 1364078 A
Description (OCR text may contain errors)
A. C. CREHORE.
TELEGRAPHiC ALPHABET OR 0005.
APPLICATION FlLED DEC. 13, I918.
- Patented Jan. 4, 1921.
New Code Wheafstone FICLI wEc 1.
S e}. s a u do w v xoz ory Mg 4 mmmwwmmmmmmmMmmmmmmmm T. I" I" mm at a ws hmru f klvw oPxz Jqy 12 4567s9wnmwmwwwmwwmw%%%% UNITED STATES ALBERT CUSHING GREHORE, OF YONKERS, NEW YORK.
TELEGRAPHIC ALPHABET OR CODE.
Application filed December 13, 1918.
T 0 all whom it may concern:
Be it known that I, ALBERT C. CnnHoRn, a citizen of the United States, and a resident of Yonkers, in the county of W'estchester and State of New York, have invented certain new and useful Improvements in T elegraphic Alphabets or Codes, of which the following is a specification.
My invention relates to telegraphs in which messages are transmitted by a dot and dash system of impulses or fundamental currents and are recorded at the receivingstation upon a tape or other device by which they are rendered visible and the message is capable of being read by the eye from the visible record.
The primary object of my invention is to make it practicable to transmit and re ceive a given number of messages over a cable, land wire or by so-ctlled wireless in a shorter time than it is practicable by other methods.
The invention is particularly applicable to those systems of telegraphy employing but two conditions of current on the line, a positive or a negative, and never the third condition of a Zero current as in cable systems, although in its broader aspect my new code or system of signals possesses advantages in reducing the total time consumed when employed in telegraphs in which a zero current interval ensues between impulses and the impulses or conditions of current upon the line are always of the same polarity.
For the purpose of illustrating my improved system the same will be compared, however, with the well-known Wheatstone system of telegraphy in which the transmitter produces changes of polarity on the line in sending signals and in which there are no Zero intervals, so that the advantages of an unbroken current are secured.
In the IVheatstone system as in other systems, it is well known that the different characters of the code are made up of dots and dashes, the dots consuming a unit interval of time and the dashes requiring three times as much time as the dot. Or, in other words, one dash is substantially equal to three dots while the space between the elements of a character is made equal to one dot. In this IVheatstone and similar systems like the Morse, the dashes are all of the same length. In my improved system, instead of the dashes being of the same Specification of Letters Patent.
Patented Jan. 4, 1921.
Serial No. 266,562.
length as in the Morse or IVheatstone, they are of different lengths as respects one ariother. This difference of length may be extended to three lengths of dash or even to a greater number, but with an alternating current system of transmission the required saving in the total number of cycles or impulses required to transmit a message may be attained by using three different lengths of dash, which in the code are arbitrarily combined with the dots or unit lengths of impulses and with one another after the general plan of the dot and dash system to secure different characteristic signals assigned ordinarily to the different letters of the alphabet.
Contrasting my improved code with the ordinary IVheat-stonc or hiorse code in which the dash is supposed to be three times as long as the dot and all the dashes are of the same length, my improved code employs three or more different lengths of dash, one twice as long as the dot, the second three times as long and the third four times as long and so on for additional lengths of dash should it be desired to use the same. However, with three different lengths of dash a substantial saving in the total length of time consumed in the sending of a message may be realized as indicated.
In the accompanying drawings I have shown in a table and side by side in Figure 1 the heatstone code and my code and the total number of impulses or units of time expended in sending the whole alphabet.
Fig. 2 shows by comparison in the length of record, the saving effected in transmitting a particular message or sequence of words.
In the IVheatstone system and as seen by the table, the dots being taken as a unit, the dashes are approximately three times the length of the dots while the spaces between the elements of a character are equal to one dot. As required in the I'Vheatstone system, the spaces between characters would be equal to three dots. In my improved system I use a dot which, as before, is the unit of time expended but the dashes, as will be seen by examination of the various characters, vary in length from the dot and respectively, as compared with the dot itself, are twice, three times, and four times as long as the dot. Or, in other words, if the space between the fundamental signals of any character be taken as equal to one dot and the length of the dot with its immediately following space be taken as two units, my improved new code uses four fundamental signals having lengths, when the following space interval after each dot and dash is included, of two, three, four and live respectively.
In the table of comparison the necessary space between letters or characters is given for the il'heatstone system and for my systom, the length of the space in the lVheatstone being, by reason of th character of the transmitter employed, necessarily three unit spaces while is possible, by using a proper transmitter and employing currents of different polarity, to reduce this space when my improved system is employed, to the length of two units of time. Against each character on the table at the right thereof appears the total number of impulses required to transmit the character with its usual following spaces.
By in improved system or alphabet it becomes possible to send the whole alphabet with a total number of semi-cycles equal to 19L. as compared with 292, required for the Wheatstoue system. The ratio of these numbers does not represent the true ratio in sending traffic, however. because the frequency of occurrence of the different letters must be allowed fol. The actual ratio is much better, commercially considered, than this figure on this account.
The received signals as drawn beneath each character on the table represent the record as it would appear by using a form of receiver responsive to reversal of current and in which the marker never leaves the paper and moves back and forth between two fixed stops rather than the record of the ordinary lVheatstone receiver, in which the marker moves perpendicularly to the paper and leaves it during the negative or so-called spacing intervals.
My improved system produces a record easier to read than the record of the siphon recorder or direct-writer record. In these it is now customary to prefer the block systems in which there are four different len ths of blocks to be distinguished in the alphabet not including numerals. as in the letters e, i, s, and h. In my new code these blocks are never more than four Y units long above, the positive pulses, and
three units long below, the negative pulses. Below one unit separates the signals composing one letter, two units separate letters and three units may separate words. By
-lookin for the three unit saaces below eye although it may be assisted by a scale of time units with uniform divisions which exactly match the time units of the record but this is not at all necessary.
The drawings Fig. 2 show a sample message, as recorded, reading: It is now clear that in order to win the war we must, the longer of the two records embodying the lVheat-stone code and the shorter the new code and each having the same time unit or semi-cycle. The saving of time is very apparent.
In the drawings the upper 3 lines embody the longer record of said message sent by the Wheatstone code and the lower 2 lines the shorter record of the same message recorded by use of my new code.
Although I have illustrated my code by a comparison with the Wheatstone system of telegraphy, yet there are distinct advantages over the well known cable system of transmission by the Continental Morse code, in which the dots and dashes each require the same length of time, namely the semicycle. In this method, by reason of the fact that the dots and dashes are distinguished from each other by the direction of the current, a positive current signifying a dot or dots, and a negative current a dash or dashes, it is not necessary to employ any space intervals at all in any single character, so that a single unit of time, the semicycle, suffices for the space between characters or letters as compared with two units in my code, or with three units in the lVheatstone system.
A consideration of the three methods, the well-known cable system, the Wheatstone system, and my new system would seem to give the preference, as regards time of transmission, to the present cable system. There are other important factors, however, that enter into the account in determining the preference. As a matter of fact it is estimated by the telegraph companies now employing the cable and the Wheatstone methods that it requires approximately 2.05 times as many semi-cycles of time to transmit a given large amount of work by the lVheatstone system as by the cable system. \Vcre it not for this handicap inherent in the two different methods, arising from the fact that the dots and the dashes have the same minimum length of time, the semicycle, and that no space between dots and dashes in a given character is required in the cable method, although the same Morse code is employed in the two systems, were it not for this handicap the advantage would be with the VVheatstone system. The cable method is inferior to the lVheatstone method from the electrical transmission viewpoint because of the employment of the third condition, the zero electromotive force interval in the cable method. The
disadvantages thus introduced are twofold. First, the use of a zero period makes it necessary to await the natural time of discharge of the cable during this interval, it not being under the control of a transmitted electromotive force. Second, it is necessary to employ a receiver which can show in the record at least three instead of two conditions, namely a positive, negative and zero condition. The receiver must be supplied with a spring or its equivalent that operates to bring the record always to the same condition or position when all governing electromotive forces are removed from the cable. The spaces between characters and words are indicated by a return of the record to this zero position. A receiver of this character has not been made that will equal the speed performance of a more simple receiver responsive to but two conditions, for example, the polarized relay employed in the Wheatstone system.
In other words, the handicap above mentioned for the Wheatstone system, namely the ratio of 2.05 times as many cycles as required for the cable system, should be reduced by a certain amount by the above considerations. That is to say, it becomes pos sible in the Wheatstone method to employ a shorter semi-cycle of current or shorter time unit than is possible in the ordinary cable method where there is a zero interval due to the electrical conditions alone.
By my invention this handicap of the Wheatstone method above referred to as 2.05 over the cable code. is reduced by a considerable amount, and at the same time all of the electrical advantages from the transmission viewpoint that are characteristic of the Wheatstone system are retained, and a system is provided which becomes a real competitor of the present cable system. It is estimated that the ratio of 2.05 above referred to is reduced to approximately 1.37 by the use of the code described herein, which is a considerable reduction. If, then, the advantageous electrical conditions permit of employing shorter semi-cycles of current in a ratio exceeding approximately 1.37 to the cable method now in common use, there is a distinct gain in the time of trans mission of a given amount of work over the cable method.
It may seem to some that the comparison made between my system and the Vheatstone system is not well chosen, it being contended that the new system competes with the present cable system, because the Wheatstone system is not now generally applied to cables. The reasons for this have been pointed out above, one of these being the handicap of the method of interpretation of the signals. Another reason is that the polarized relay ordinarily employed in the lVheatstone system has never been perfected to operate on the small values of current which alone are available in long cables.
Part of the electrical advantage referred to would be lost if the common forms of cable relays are substituted for the polar relay of the lVheatstone system, the former depending upon the moving coil principle as in a siphon recorder.
But by modifying the polarized relay so that it will operate on currents of the order of magnitude of the current available in cables, the advantages of the use of my new code for cables are a maximum as above shown. The advantages of the new system as applied to cables will naturally be greater as the length of the cable is less, the longest cables probably affording the least proportionate increase.
lVhat I claim as my invention is:
1. The herein described improvement in telegraphing by the dot and dash code or system, consisting in employing dashes of different length as respects one another, combined with one another and with dots for the different characters or signals and with uniform spaces between the elements of the characters or signals of the code or system.
2. The herein described improvement in telegraphic systems employing a code and visible record to be read by the eye, consisting in arbitrarily combining four fundamental signals having length, when the uniform spaces of one unit between elements of a character are included, equivalent respectively to two, three, four and five of the unit impulse or semi-cycle of current employed.
3. The improved telegraphic code or alphabet herein described made up from dots and dashes, the dashes being of different length as respects one another and the spaces between the elements of the several charaeters making up the code or alphabet being uniform.
Signed at New York city, in the county of New York and State of New York, this sixth day of December, A. D. 1918.
ALBERT CUSHING CREHORE.
lVitnesses HELEN E. BRADY, V. M. BUCKLEY.