US2339999A - Telegraph storage and switching system - Google Patents

Description

Jan. 25, 1944. G. G. LIGHT TBLEGRAPH STORAGE AND SWITCHING SYSTEM Filed Jan. 29, 1942 M Nom m l I I l I l I I 7 Patented Jan. 25, 1944 UNiTao STATES PATENT ortica TELEGRAPH s'ron sY This invention 'relates to printing telegraph switching systems wherein messages received at a switching station are temporarily stored in perforated tape pending the completion of switching operations whereby the stored messages are relayed to their ultimate destinations.

In systems of this character each message is usually succeeded by a predetermined vend-of-k AGE AND SWITCHETG STEM George G. Light, Kew Gardens, N. Y., assignor to rllhe Western Union Telegraph Company, New York, N. Y., a corporation of New York Application January 29, 1942, Serial No. 428,648

8 Claims. (Cl. 178-4) message signal which is also perforated in .the

tape and is used to control the tape handling apparatus including the perforator and the transmitter. Signals for this function are selected so that the probabilitt7 of their occurrence in the body of a message is, for all practical purposes, negligible. Systems utilizing signals of this character are disclosed in Patent 2,193,811 granted March 19, 1940 to Blanchard et al., copending application of Blanton, Serial No. 299,408, filed October 13, 1939, now Patent 2,279,295, granted April 4, 1942, and copending application of Light et al., Serial No. 350,402, filed August 3, 1940.

An end-of-message signal generally includes a plurality of characters, some of which, when detected by the transmitter, control the stopping of the transmitter. Other characters control' the operation of selector contacts in the perforator which by themselves or in conjunction with other tape controlled contacts control apparatus for feeding out of the perforator enough tape follow'- ing the stored message so that the last message character will reach the transmitter pins. illustrative form of apparatus for feeding out additional tape by a perforator is disclosed in Patent 2,252,852 granted August 19, 1941 to Hoover.

In the start-stop system disclosed herein and embodying the instant invention, there is located at a switching station a perforator normally unresponsive to message signals received at that station but which, under the control of Special switching signals, may be used to store received message signals in a perforated tape for subsequent retransmission to a remote station. Following eacli message or series of messages to be retransmitted an end-of-message signal is utilized to actuate selector-controlled contacts in the perforator to render the perforator unresponsive to subsequently received signals. For reasons of uniformity of operating routine the end-ofmessage signal also includes one or more charact-ers following the disconnect characters to-control the feeding out by the perforator of addif tionaLtape. It is contemplated that elsewhere in the system there usually will be another perforator which is at all .times responsive toline signals. The tape feed out character or characters of the end-of-message signals will, of course, be received by 'such a perforator. With respect to the normally unresponsive perforator, however, it is only in the most favorable circumstances that a tape feed out character will be received before the selector mechanism of this perforator is rendered unresponsive under the control of thepreceding characters of the end-ofmessage signal.

Hence, it is an object of this invention to provide a telegraph system in which means are employed for conditioning a perforator for feeding out tape following the disconnection thereof from a signal receiving circuit. y y

Another object of the invention is to provide means responsive to a disconnect signal to locally control the actuation of a predetermined selector operated contact of a perforator after said perforator has been rendered unresponsive to signals received from a signaling circuit.

A further object of the invention is to provide, in apparatus whereby a telegraph signal receiver is rendered unresponsive to said signals under the control of contacts actuated by the selector of said receiver, means also controlled by said contacts to condition `the selector, after being rendered unresponsive to telegraph signals, whereby another contact controlled thereby is actuated.

An additional object ofthe invention is to pro vide a relay organization whereby the responsivenessor unresponsiveness of a telegraph signal receiver is vcontrolled and-which, after rendering the receiverunresponsive to signals, conditions the receiver for the actuation of a predetermined selector operated contact thereof.

Still another object of the invention is to provide a relay organization operable under the control of selector operated contacts of a telegraph signal -receiver to render the receiverunresponsive to further signals and to controlthe actuation of another selector operated contact of the unresponsive receiver.

Another object of the invention is the provision in a telegraph switching system wherein facilities are employed for operating a predeter- .mined selector controlled contact of a Areceiving subsidiary objects of the invention will be evi dent from the following description of an illustrative embodiment thereof taken in conjunction with the single gure of the accompanying drawmg.

Having reference to the accompanyingdrawing, there is disclosed a party line start-stop telegraph system extending through stations A, B, C and D. The printing telegraph apparatus at these stations is connected in a series line circuit L. At station A the line circuit is connected to the selector mechanism of a printer-perforator I by means of which perforated tape 2, which also contains a printed record of the received signals, is prepared for the control of a tape transmitter 3. Stations B and C 'are `provided respectively with printers 4 and 5 by means .of which telegraph signals may be transmitted and received. These stations are also provided respectively with normally closed keys 6 and 'I through which the line circuit is connected. At station D the line circuit is connected through a printer 8 by means of -which telegraph signals may be transmitted and received vand also through a repeating relay :9. This rstati-on is also provided with a printer-perforator III which is normally unresponsive '-to telegraph signals but which may be rendered responsive .thereto at certain times in a manner to be described. This printer-perforator l'also prepares a 'control .form or tape II in which predetermined groups kof received signals are perforated and also .recorded in printed form. The taps .Il is fed through a `tape transmitter 4I2 for retransmission 'to a remote station connected Ito station D.

The tape transmitters 3 'and '.I2 .respectively at stations -A and D may be Aci the type disclosed in Patent 2,172,269, granted September 5, 1939, .to Angel. The printer-perforators I and I0 respectively at stations Aiand D may be of any suitable type, numerous examples o which are .to be found in the prior art, such .as that :shown in rpatent 2,174,731, granted October T3, 1939, to

" tions.

mer which is actuated for each operation of the selector mechanism to control the apparatus employed to perforate the tape. The contact I6 will be referred to hereinafter as the punch hammer contact, and the contacts I3 and I4, respectively, as the carriage return and unshift contacts of the printer-perforator. The printerperforator I at station A is also provided with auxiliary contacts similar to those of the printer- 4perforator I0.

'Stations A and D are known as switching sta- At .station A, for example, where copies of all messages transmitted over the line circuit `L are received, facilities are provided similar to vthose disclosed in the copending application of Y Blanton, Serial No. 299,408, whereby certain of message appearing in the tape.

Dirkeset al., or Patent 2,143,1828 grantedJ'anuary 10, '1939, to Dirkes `e't al. The Eformer patent covers a combination telegraph printer .and perforator yfor use with start-stop signals such 'as those employed in the instant system, While the latter coversa similarin'strument better adapted for use with multiplex signals. Consequently, in

the present system, either of 'the above devices f may -be used 'by making suitable obvious modications therein. The instrument coveredby Patent 2,174,731 is susceptible of use 'in lthe present system when -modied in 4accordance with "the disclosure of Patent 2,143,828 to 'includ'efs'elector operated auxiliary contacts.

Thegprinter-perforator Ill includes -fa `.normally open contact I3 lwhich 4is similar to the contact disclosed in Patent 2,143,328 land is 4closed after a carriage return selectioni'slmadeby -the printerperforator. A similar contact Ill is closedafter an uns'hif or letters shift selection is made by the printer-perforator. Both of these cc-ntacts are closed underthe'control of the storage mechanism to which the 'received signals Aare of 'a suitable linkage operated by the punch ham- Such a message for retransmission from station A `may originate fat any of the other stations in the system. In accordance with the disclosure of the copending application .of Blanton referred to, each message is followed by an end-of-message signal in which yare included predetermined characters which, when detected by the tape vtransmitter 3, stop the 'transmitter and also one or 'more other predetermined characters by means of which selector `contacts of the printerper-forator `I Aare actuated to effect the feeding out by the printer-perforator of enough additional tape to insure that the last message character and the transmitter control characters of the `end-of-message signal reach the transmitter.

Stations B and'C may communicate with one another, or with vstation D at which the printer '8 responds to the received signals. Station D may also communicate with either or both of stations Band C, land as previously stated stations B, C and D communicate with station A. Also, "stations B and C may communicate with station Dat times when Vthere are messages to be retransmitted from station D to other remote stations -connected thereto ina manner similar to that of station A.

Normally all communications over the system operate vonly the printer 8 at station D, the printer-perforator I0 at 'that station being normally unresponsive to fthe received signals. When it is desired to render 'the printer-perforator I0 at station D responsive to received signals so 'that tape may 'be Aprepa-red to control the transvmitter I2 for the purpose of retransmitting the transmit a predetermined signal for the purpose -o'f conditioning the printer-perfora'tor Il] for operation. f

At station 'D the line relay 9 is operated in response to all marking signals including the rest signal which is applied to the circuit while it is idle. When thisrelay is operated, by means `of its second .make :contact negative battery is applied i'to the control gridy of a yvacuum tube I9,

the cathode of which is connected to ground. Consequently, in response to marking line signals, the tube I9 is maintained non-conducting. The input circuit of this tube is provided with a delayV circuit comprising the parallel connection of a condenser 2G and a resistance 2| shunted between the control grid and the cathode. The constants of this delay circuit are so chosen that the short releases of the line relay 9 in response to received spacing signals whereby the negative potential is momentarily disconnected from the control grid of the tube are ineiective to start conduction in the tube I9. Consequently, relay 22 is in its released position so that battery is connected through its lett hand break contact, the Winding of relay 23 and the first right hand make contact of this relay toground. Withrelay 23 operated, battery is connected through its left hand make contact, the break contact of relayu24 andthrough the winding of the selector magnet I5 of the printer-perforator IO to ground. As a consequence of this connection the operations of the first make contact ofvrelay 9 in response to the received signals are ineiective to produceresponses by the printer-perforator. i

Assume that station C desires to transmit a message to station D for retransmission to aremote station connected thereto. `With the line circuit idle, the operator at station C opens the key 1 for a period of time which is longer than the time required to send a message character. In response to this open line condition relay 9 releases, thereby disconnecting at the second make contact thereof negative battery from the control grid circuit ofthe tube I9. While this contact is open, the negative potential previously applied to the control grid of the tube is permitted to leak oi sufficiently to start conduction in the tube. The space current for the tube is derived from positive battery connected to the winding of relay 22, thereby operating this relay which is immediately locked through its right hand make contact to ground through the second right hand make contact of relay 23. It is noted that this latter relay does not release immediately 1 in response to the opening of the right hand break contact of relay 22 for the reason that this Contact is shunted by the third make contact of the line relay 5 which is still released at this time. ated, however, in response to the closure of the key 'I at station C, the holding circuit for relay 23 is opened at the third break contact of the 1 line-relay, and relay 23 releases. Substantially concurrently therewith the closure of the second make contact of the line relay 9 renders the tube As soon as the line relay is operrelay tothe printer-perforator selector magnet.

I9 non-conducting, but the release of relay 22 is not dependent upon this operation but upon the release of relay 23 so that it is after the release of relay 23 that the connection to battery through `the left hand break contact of relay 22 is re-established. When this occurs, it is no longer possible to re-energize the locking circuit of relay 23 vso that it remains released :for the duration of the operative condition ofthe printer-perforator I0.

The disconnection of battery by the opening of the left hand make contact of relay 23 from the holding circuit through the selector magnet I5 of the printer-perforator conditions it for operation in response to received line signals. It is noted that there is no immediate opening of the circuit through the selector magnet I5 for the reason that battery is applied through the rst make' contact of relay 9 and the break contact oi Now it is seen that subsequent operations of the line relay in response to received message signals cause the selector magnet I5 of the printer-perforator II] to respond, whereby these received signals are perforated and printed in the tape I I. The attendant at station D places the plug I8 in a jack associated with the circuit connected to the remote station designated, in, the address oi the message, and the message is retransmitted to said remote station by the" transmitter I2.

Following the reception of the body of the message at station D, the end-of-message signal is received thereat and, in this case, comprises two successive carriage return signals (only the fourth impulse marking) followed by an unshift signal (all impulses marking). In response to the iirst carriage return signal the selector operated contacts i3 and i6 are closed momentarily. The closure of the carriage return contact I3 completes a circuit from` ground through the second break contact of relay 26, the Winding of relay 21, and the break Contact of relay 28 to battery. The closure of the punch hammer contact I5 of the printer-perforator connects ground through the first break contact of relay 26 to one terminal of the right hand winding of this relay thereby short-circuiting this winding since the other terminal thereof is also connected to ground. Relay 2l is operated and closes a path through its make Icontact from its winding to the right hand winding of relay Z. As soon as contacts I3 and IS open, the short-circuit is removed from the right hand winding of relay 26 which becomes energized by a circuit extending from vbattery through the break contact of relay 23, the Winding and make contact of relay 21, and the right hand winding of relay 26 to ground. In response to the second carriage return signal contacts I3 and I S are again closed and by means of the lpunch hammer contact I6 a circuit is comn pleted from ground through the iirst make contact and left hand windinor of relay 26 and the winding of relay 28 to battery. Relay 28 is operated and opens the locking circuit through the winding of relay 2l and the right hand winding of relay 25.5, Relay 2l releases immediately but relay 26 is maintained operated -for the duration of the closure of contact I5 by reason of the energization of its left hand winding. When this contact is opened subsequently, relay 25 also releases to `restore it to normal. However, before this occurs, the closure of the carriage return contact I3 of theV printer perforator completes a circuit from ground through the second make contact of relay 2t, the winding of relay 23 and the leit hand break contact of relay 22 to battery, thereby operating relay 23 which is immediately locked to ground through its first right hand make contact.

The closure of the' left hand make contact of vrelay 23 connects battery through the second ina it possible to .establish the previously described holding circuit to the selector magnet i5 of the printer -erforator.

When this relay does release, 'relay '24 is .cleenergized by the opening of the first make contact of relay 25. `Substantially simultaneously with the deenergization of relay 24 the holding circuit through the selector magnet I5 of the printer' periorator is opened at the second make contact of relay ,25. This circuit remains open until the break contact of relay 2li closes to again rse-.establish the holding circuit. The time elapsing between the opening oi the .contact of relay 25 and the closing of the .contact of relay 24 is approximately the time duration of a start impulse of the start-stop telegraph signals. Consequently its effect upon the selector mechanism of the printer perforator Ill-is the same as the eect of a start impulse and causes the mechanism to perform one cycle. Since immediately following the local generation of the start impulse, the winding of the selectorv magnet I5 is immediately energized. and maintained in such condition, the effect upon the selector mechanism is the same as that which would be produced by the reception of an unshift character in which all impulses of the code are marking. The result of this operation is the actuation of the contact I4 which is closed under the control of the selector mechanism in response to the local generation of an unshift signal.

As previously indicated there is a possibility that the unshift character of the end-of-message signal will be received at station D with suicient promptness to enable the repetition by the line relay 9 of the spacing start impulse and at least a portion of the rst of the all marking impulses of the unshift character to the selector magnet I5 of the printer-perforator before the auxiliary contacts I3 and IE respond to the second carriage return character to operate relay 23. If relay 25 were permitted to release immediately following the operation of relay 23, the locally generated spacing signal would 'be impressed upon the selector magnet of the printer-perforator while the selecting mechanism controlled thereby is responding to the repeated unshift character. Thus, the selection would be made in accordance with a character signal having a spacing impulse instead of in accordance with an all marking character signal. In that case the unshit contact I4 would not be operated as desired. Hence the release of relay '25 is delayed suiciently to insure that the selecting mechanism of the printer-perforator i0 will be in a rest condition even though it is caused to respond to an unshift character received from the line at the time that the locally generated unshift character is being prepared for impression upon the selector magnet I5.

The mechanism of the printer-perforator H3 is 'left in this idle condition with the`contact I4 closed. As the tape I I is fed through the transmitter I2, with no additional tape being prepared for the time being, the loop of tape between L tus of this general character is disclosed in Patent 2,252,852 to Hoover. Once opera-ted, .this `apparatus functions to .condition the printer-perforator Il) to prepare a predetermined lengtho tape. In this case, since the selector mechanism of the printer-perforator is locked i-n laccordance with the selection of an unshift character, the additionally prepared tape will have perforated therein a plurality of successive unshift characters. Following the metering out of a 'predetermined amount of tape, the feed out apparatus 30 restores the printer perforator I0 to its normal idle condition in a conventional manner and by the time that the tape loop again shortens to actuate the contacts controlled thereby to stop the transmitter I2, the last message character will have been stepped through the transmitter.

In the event that in the course .of the transmise sion of the message a single carriage return signal is sent, the contact I3 of the printer-perforator I0 will be closed to operate relays 2-6 and ,2l in the manner described. So long as the following character is anything but a carriage return signal, the contact I3 will not be closed on the following cycle of operation of the printer-perforator but the contact I6 will be closed. As in the previous case, the closure of this contact opera-tes relay 28 momentarily to release relays 26 and 2,1 thereby restoring them to their idle condition. The failure of the `contact I 3 to close prevents the operation of relay 23 and thus prevents the printer-perforator from being prematurely ren.- dered unresponsive to the received signals.

vThe nature of the invention may be ascertained from the foregoing description of an illustrative embodiment, it being understood that changes xin the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the invention.

What is claimed is:

l. In a printing telegraph system, a signal re.- ceiver having a plurality of contacts operable by the selector mechanism thereof, Vmeans controlled by one of said contacts responsive to a disconnect signal received by said receiver for rendering said receiver Yunresponsive to subsequently received signals, and means controlled by said rst mentioned means for conditioning the selector mechanism of said unresponsive receiver to operate another o-f said contacts.

'2. In a printing telegraph system, a line circuit means for transmitting over said circuit groups *i of intelligence signals and an end-of-message `of said signal Vfollowing each of said groups, a signal receiver having a plurality of selector operated contacts, means for operatively associating said receiver with said line circuit, Vmeans including one contacts rresponsive to said end-of-message signal for dissociating said receiver from operative relation with said line circuit, and means controlled by said dissociating means yfor condit1on1ng the selector mechanism of said receiver `for the actuation of another of said contacts. 'i 3. `In a printing telegraph system, a tape perforator having a plurality of selector operated contacts, means for impressing telegraph signal-s including message characters and switching characters upon the selecting mechanism of said perforator, means to operate said perforator in response to said message characters to prepare tape representative of said characters, means includ- :mg one of said contacts operable in response rto said switching characters for rendering the selector mechanism of said perforator unresponsive to subsequently received telegraph signals, means controlled by said switching signal responsive means for conditioning the selector mechanism of said unresponsive perforator for the actuation of another of said contacts, apparatus to condition said unresponsive perforator for the ejection of a predetermined length of tape, and means including said other selector operated contact for operating said tape ejection apparatus.

4. In a start-stop printing telegraph system, a tape perforator having a plurality of contacts selectively actuated by the selector mechanism thereof, means to render said selector mechanism normally unresponsive to received telegraph signals, means operable to render said periorator responsive to received signals, means responsive to an end-of-message signal for operating one of said contacts, means operable under the control of said contact for rendering the selector mechanism of said perforator unresponsive to received signals, means operable by said contact controlled means for generating locally and impressing upon said selector mechanism a start impulse, means for conditioning locally said unresponsive perforator for ejecting a predetermined length of tape, and means including another of said contacts controlled by said selector mechanism in response to said locally generated start impulse for actuating said tape ejecting means.

5. In a printing telegraph system, a tape perforator having a selector mechanism responsive to telegraph signals, a plurality of contacts, means controlled by said selector mechanism to selectively operate said contacts, means controlled by one of said contacts responding to a switching signal for rendering the selector mechanism of said perforator unresponsive to telegraph signals, means responsive to said contact controlled means for generating locally and impressing upon the selector mechanism of said perforator a signal representative of a predetermined character, means including said selector mechanism to actuate another of said contacts in response to said predetermined character, means to control the ejection of a predetermined length of tape from said unresponsive perforator, and means including said other contact for operating said tape ejection means.

6. In a printing telegraph system, a telegraph signal receiver for recording signals in a tape and having a plurality of contacts selectively operable by the selector mechanism thereof, a telegraph signal repeater, a relay organization, means including said relay organization for controlling the responsiveness or unresponsiveness of said receiver to said signal repeater, means including one of said selector controlled contacts for conditioning said relay organization to render said receiver unresponsive to the repeated telegraph signals, means including said relay organization for generating and impressing upon the selector mechanism of said unresponsive receiver a signal representative of an unshift character, means including said selector mechanism to operate another of said contacts in response to said unshift character, a tape operated contact controlled in part by the cessation of tape feeding by said receiver, means for conditioning said receiver for the ejection of a predetermined length of tape,l

and means including said other contact of said receiver and said tape operated contact for operating said tape ejection means.

'7. In a printing telegraph system, a signaling circuit, a iirst signal receiver responsive at all times to signals transmitted over said circuit, a second signal receiver responsive only at certain times to signals transmitted over said circuit, each of said receivers employing a record tape for said signals and having selector operated contacts operable in response to predetermined end-ofmessage signals, means for transmitting end-ofmessage signals each comprising a plurality of successive characters, means including contacts of said receivers responsive to a last one of said characters to control the ejection of a predetermined length of tape, means including contacts of said second receiver responsive to first ones of said characters when said second receiver .is responsive to signals to render said second receiver unresponsive to transmitted signals, and means operable after the unresponsive conditioning of said second receiver to actuate the tape ejection means of said second receiver.

8. In a telegraph system, means for transmite ting successively first and second different character signals, a signal receiver having a selector mechanism and rst and second contacts operable respectively thereby in response to said first and second character signals, the operation of said contacts occurring at a predetermined time following the receipt of the complete character signal, means including said rst contact to prepare for the inoperative conditioning of said receiver, means for delaying said inoperative conditioning for a period of time'suicient to permit the complete reception of said second character signal if transmitted immediately following the rst character signal, and means controlled by said inoperative conditioning to generate locally and impress upon said selector mechanism a character signal similar to said second character signal.

GEORGE G. LIGHT.

Images