US2000764A - Communication system - Google Patents

Description

wl s. LEMMON ET AL COMMUNICATION SYSTEM Filed Feb. l0, 1954 Patented May 7, 1935 UNITED STATES PATENT OFFICE Y COMMUNICATION SYSTEM Walter S. Lemmon, New York, N.

Y., yand oxyde J. Fitch, Jersey City, N. J., assignors to International Business Machines Corp., New York,

16 Claims.

The present invention pertains to a novel communication system designed for the sending of messages by electrical impulses and is applicable to radio, carrier current and line transmission, etc. V

The invention embodies the use of synchronized disks or distributors at the transmitting and receiving stations for completingthe transmitting and receiving circuits respectively similar to the synchronizing system disclosed in the co-pending application Serial No. 684,362 filed August 9, 1933. At the sending station, the impulse is not transmitted until contact of reof the distributor corresponding to the actuated key for the character to be sent; and at the instant of contact, the impulse is sent out and caused to register the same character at the receiving station, due to the synchronism of the contact disks or distributors.

In the present invention the characters are transmitted by the depressionof key bars.

receiving mechanism.

The principal object of the invention is to matic View of the apparatus. Inasmuch as the receiving apparatus and sending apparatus are alike, a detailed description of only one of them Will suice.

The transmitting apparatus, (and also the receiving apparatus) includes a conventional or modified typewriter having a series of lettered and numbered pivoted key bars I. Over the bars is mounted a roll 2 held in a slidable carriage (not shown) in the usual'manner so that it is moved one space on depression of any key bar. Each key bar has associated therewith a type bar 3 adapted to strike against the roll 2 on depression of the corresponding key bar. This action is effected through a suitable linkage 4 between each key bar and its corresponding type bar. A sending distributor 5 carries a series of spaced contacts 6 corresponding respectively to the various characters on the type bars I. The contacts are engaged in rather rapid succession by a rotary contact arm 1 driven by a chronism with the similar device at the other end of the transmission circuit and which is fully described in the co-pending application stated hereinbefore.

Each 'of the key branch condenser circuit; from a contact 9 disposed respectively beneath the `key bars, and normally spaced from the latter when the bars are in their normal or raised position, a line I0 is extended separately from each lower contact to individual condensers II, said condensers in turn connected to a corresponding key bar, so that upon depressing the key bar, its corresponding condenser if charged previously is discharged. Each of the key bars is comprised in a .circuit embodying common conductors I2 and I3 extending to rotary arm l, in 'which are comprised a sending switch I4 closed 'at the sending end, resistor I5, and condenser charging battery I6. 'Ihe corresponding switch is open at the receiving end, as will be more fully described hereinafter. From the distributor contacts 6 conductors I 1 extend separately to xed contacts I8 positioned over the key bars. The latter contacts are engaged by the corresponding bars I when the latter are in raised or released position and at such time close a corresponding condenser charging circuit consisting of said bar I and contact I8, contact 6, rotary arm 1, conductor I3, battery I6, resistor I5, switch I4, conductor I2 and corresponding condenser II. Thus when any of the bars I is depressed, the corresponding condenser II will be short cirmotor 8, which is in synbars I is comprised in a4 cuited and discharged through the bar engaging contact 9 and conductor I6. A sending circuit is connected to the terminals of resistor I5 and comprises the usual transmitting means.

The transmitter 20 as shown has one of its output terminals connected to an antenna 2I and its other output terminal 22 grounded in the usual manner. As mentioned previously this invention is applicable to radio, carrier current and line transmission, for this purpose a transmission line 2Ia is shown connecting the stations.

In the operation of the device as thus far described, it will be seen that the depression of a key bar I rst breaks its condenser charging circuit to short circuit and discharge the condenser II. On the return of the bar it engages its corresponding upper contact I8 and when the rotaryA arm engages its contact 6 corresponding to the depressed key bar, the condenser charging circuit is completed, so that the drop across resistor I5 caused by charging current pulse activates the connected sending circuit I9 and transmitting apparatus 26, as a result of Winch an impulse is transmitted.

In order to insure correct operation 'of the transmitting system upon starting', the normally closed switch 40 included in the input circuit to the radio or line transmitter is opened until the individual condensers II, which may have been discharged by leakage, are fully charged by having all the distributor contacts 6 engaged successively by the rotary arm 1 in a manner described above, and in this manner prevent operation of the receiving system which will now be explained.

The receiving circuit of each apparatus includes a receiver 23 having one of its input terminals grounded at 24 and its other 4input terminal connected to an antenna 25 or line 2Ia to receive the impulse sent out from transmitter 20 in the usual manner.

Beneath each of the key bars I is a solenoid 26 adapted to operate on a plunger 21 depending from the bar, so that when a given solenoid is energized by the means presently to be described, the corresponding key bar will be depressed to actuate the corresponding type lever 3. The receiving circuit is governed by a receiving distributor 28 carrying elongated spaced contacts 29 corresponding in number and position to contacts 6 on sending distributor 5.

The contacts 29 are of greater length circumferentially than contacts 6 so as to hold the receiving circuit closed for an interval suicient to enable energization of the solenoids 26 and operation of the type bars 3 as well as to allow for slight inaccuracies in the synchronism of the rotary arms 1 and' 3D respectively. The rotary arm 3D wipes over the contacts 29 and is driven by a motor 3l and rotates in synchronism with rotary arm 1 as previously disclosed, so that the arms of both distributors are in engagement'with similarly identified contacts at any instant.

The contacts 29 are connected separately to its corresponding solenoid 26 by lines 32. A common conductor 33 extends from one of the output terminals of receiver23 to the remaining terminals of the solenoids. The other output terminal of the receiver is connected by conductor 34 to battery 35, the other side of the battery is extended to rotary arm 30 by line 36 including switch 31.

On reception of an impulse at the receiver 23, the receiving circuit is energized instantaneously and includes conductor 34, battery 35, conductor 36, switch 31, rotary arm 30, any contact 29 and the particular conductor 32 and solenoid 26 corresponding to the contact 29 engaged by arm 30, and conductor 33 back to receiver 23. Upon completion of said circuit the particular said solenoid is energized causing the character correspondingto the contact 29 to be printed on the roll 2. The characters printed will appear in the same order in which they are sent inasmuch as the said arms 1 and 30 are always in like relationship to the contacts engaged thereby due to their synchronous rotation.

In order to bring the sending rotary arm 1 into register with receiving arm 36, with respect to the contacts of distributors 5 and 28, the sending operator rst transmits a predetermined signal for a given interval, whereupon the receiving operator sets the arm 30 on a given contact 29 corresponding to the predetermined position of the arm 1 on the sending distributor.

It will be evident that the switch I4 being open at the receiving end renders the condensers II inoperative and ineffective, and in like manner the receiving switch 31 being open at the sending end, renders the receiving circuit inoperative. Thus the vapparatus installed at any station may be used interchangeably for sending or receiving on proper adjustment of the said switches.

While there has been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the following claims.

What is claimed is as follows:

l. In a communication system, capacitive reactance devices corresponding to characters to be transmitted, means to supply current to said devices, means for initiating transmission of signals corresponding to said characters, and means to effect transmission of initiated character signals upon supplying current to said devices.

2. In a communication system, means for initiating transmission of character signals, a plurality of charge accumulating devices corresponding to characters to be transmitted, means under control of initiating means for charging said devices, and means to transmit initiated character signals upon charging of said devices.

3. In a communication system, a plurality of elements for initiating character signals, means cooperating with said elements to supply energy for transmission of character signals, means under control of said initiating means for energizing rst named means, and means for effecting energization of rst named means to cause transmission of initiated character signals upon energization of rst named moans.

4. In a communication system, a plurality of condensers, one corresponding to each character to be transmitted, means for charging said condenser, a mechanism for initiating transmission of signals corresponding to the diierent characters and means under control of initiating means for effecting charging of the diierent condensers at differential times in accordance with the different characters to be transmitted.

5. A signal controlling circuit having a source of current supply, an element for initiating ow of current from said supply through the circuit, a condenser in the circuit charged by the iiow of current upon operation of said initiating element to vary the circuit characteristics, and means controlled by the circuit by and upon variation of the current characteristics to transmit a signal.

6. In a communication system, a sending malchine having charge accumulating devices,

activated upon energization of the corresponding reactance elements.

8. In a communicationv system, a sending machine having capacitive reactance elements, key bars, each associated with a reactance element, circuits operated by the correspondingkey bars for energizing said elements upon operation of the key bars, a transmission circuit connected to the rst named circuits, and means associated with the iirst named circuits to activate said transmission circuit upon energization of the corresponding reactance elements.

9. In a communication system, a sending machine having capacitive reactance elements, key bars, eachv associated with a reactance element, circuits operated by the corresponding key bars for energizing said elements upon operation of the key bars, a transmission circuit connected to the rst named circuit, and electrical impeding means associated with the rst named 'circuits to activate said transmission circuit upon energization of the reactance elements.

10. Ina communication system, a sending machine having key hars,` a condenser for each. bar, contact members corresponding to said bars and connected respectively to said condensers to receive the charging current for said condensers respectively upon operation of said bars, and a transmission circuit to be energized by the flow of charging current through said contacts to said condensers.

11. I n a communication system, a sending machine having key bars, condensers for each keybar, circuits for charging said condensers, the key bars operable for initiatng operation of its corresponding circuit, contact members corresponding to said bars and connected respectively to said condensers to receive charging current for said condensers, a transmission circuit connected to the iirst named circuits to be energized by said condenser charging current, and means associated with said contact members to complete the operation of the rst named circuits to charge the condensers and to cause the energization of said transmission circuit.

12. In a communication system, a sending machine having capacitive reactance elements, depressible key bars, circuits for energizing said elements upon return movement of the key bars. and a transmission circuit connected to the rst named circuits and activated upon energization of the reactance elements.

13. In a communication system, a sending machine having capacitive reactance elements, depressible key bars, each associated with a reactance element, circuits operated by the corresponding key bars for energizing said elements upon return movement of the key bars, a transmission circuit connected to the rst named circuits, and means associated with the first named circuits to activate said transmission circuit upon energization of the corresponding reactance elements.

14. In a communication system, a sending machine having key bars, a condenser for each key bar, circuits operated by the corresponding key bars for charging said condensers upon return movement of the key bars, a transmission circuit connected to the rst named circuits, and a common resistor connected to the rst named cir` cuits to energize said transmission circuit upon the charging of the condensers.

15. In a communication system, a sending machine having key bars, a condenser for each key bar, circuits operable by the key bars for charging its corresponding condenser upon return movement of the key bars, a resistor connected to said circuits, a transmission circuit connected to the rst named circuits to be energized upon flow of the vcharging current through the resistor, a receiving circuit sensitive to the transmission circuit, printing members associated with said key bars, electrical devices in said receiving circuit for operating said key bars and printing members, and a selecting switch for rendering either said receiving circuit or said condensers, inoperative and rendering the other operative.

16. In a communicating system, a 'printing man chine having key bars, a condenser for each key bar, circuits operable by the key bars for charging its corresponding condenser upon return movement of the key bars, a resistor connected to said circuits, a transmission circuit connected to the first named circuits to be energized upon ow of the charging current through the resistor a receiving circuit, printing members associated with said key bars, electrical devices in said receiving circuit for selectively operating said key bars and printing members, and a selecting' switch for permanently rendering either said receiving circuit or said condenser circuit inoperative and rendering the other operative.

WALTER s. LEMMON. cnYDE J. FITCH.

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