US2176963A

US2176963A - Single line telegraph repeater

Info

Publication number: US2176963A
Application number: US182140A
Authority: US
Inventors: Frederick G Hallden
Original assignee: POSTAL TELEGRAPH CABLE CO
Current assignee: POSTAL TELEGRAPH CABLE CO; POSTAL TELEGRAPH-CABLE Co
Priority date: 1937-12-28
Filing date: 1937-12-28
Publication date: 1939-10-24
Anticipated expiration: 1956-10-24

Description

Oct. 24, 1939. F. G. HALLDEN SINGLE LINE TELEGRAPH REPEATER Filed D90. 28, 1937 m I II-IlnI OCM Patented Oct. 24, 1939 UNITED STATES PATENT @FFME SINGLE LINE TELEGRAPH REPEATER Application December 28, 1937, Serial No. 182,140

14 Claims.

My invention relates to single line telegraph repeaters and particularly single line repeaters provided with means for repeating polar controlled signals.

Single line telegraph systems with a wire line with ground return have been used for interconnecting printer stations. In these systems the signals are generally composed of two types of elements only, either current impulses of opposite polarity or current impulses of one polarity with spaces or periods of no current. If the lines are so short that no re-enforcing of the signals by repeating is necessary a third type of signal elements may be introducedfor other control purposes, that is a spacing interval in the double polarity system or an impulse of reverse polarity in the single polarity make-break system.

When repeaters are used in a single line system, however, the construction and limitations are such that repeating of the three types of signal elements cannot be readily accomplished. It isy desirable, however, to provide a means for signalling different stations for establishing a con nection, or for remotely starting a motor at a station even when a repeater is included in the system. Such signals may comprise an impulse of reverse polarity in addition to the regular signalling impulses and spacings of a make-break Ysignalling system.

Itis an object of my invention to provide single line repeaters capable of repeating normal signals comprising impulses of one polarity and spaces, and reverse polarity signals.

It is a further object of. my invention to providea means whereby motor control signals may be repeated. overa single line repeater in addition to message signals.

It is a still further object of my invention to device a system which is capable of repeating message signals and also reverse polarity sig-k nals, for the purpose ofr motor control. or other purposes, for use in a telegraph circuit.

Other objects and advantages of my invention will present themselves from a reading of the particular. description given in connection with the accompanying. drawing, in which Fig.. 1 illustrates one embodiment of my invention. applied to a simple printer exchange system,.and

Fig. 2 discloses another modification of my invention which is particularly adapted for use in one form of automatic switching printer telegraph arrangements.

'Iurning now to Fig. 1,v there is shown a telegraph system in its normal idle condition. In the idle condition, negative battery extends through a Winding of line relay I, and springs of jack 2 to line 3. At the repeater station line section 3 extends through the armature and iront contact of repeating relay 4, winding of polar relay 5, and winding of repeating relay 6 to ground. Relays I, 5 and 5 will be operated as shown.

Negative battery will also extend through a iront contact and armature of polar relay 5, Winding of repeating relay contacts of relay 6 over line section I to the distant station and then through printer magnets 8, keyboard contacts 9, polar relay I (I, motor control relay II and break key I8 to ground. Relays 4, I0 and II will be operated as shown. Contacts of relay II will be held open, interrupting the power source for operation of printer motor I2.

As shown, the power source for printer motor I3 at the central station will be open at contacts of relay I4 which is deenergized.

lIf now, printer cord plug I5 is inserted in jack 2, relay I4 will operate in series with a winding of relay I, thereby starting printer motor I3. Positive battery will now extend through keyboard contacts I6, printer magnets Il, plug I5, and tip spring of jack 2 to line section 3 and then to ground through relays 5 and 6 as traced before. This reversal of battery through polar re lay 5 will cause its armature to engage its back contact, thereby reversing the current through the circuit including line section 1 and the station set. This reversal causes polar relay I0 to move its armature against its back contact, short circuiting the winding of motor control relay II, which releases and permits it contacts to extend power to motor I2 starting the motor.

The armatures of polar relays 5 and I0 will bear against their back contacts when positive battery is connected to lines 3 and 'l as just described. Due to the action of the bias springs (not shown) attached to these armatures, they will also bear against their back contacts when no battery is connected to lines 3 and 1.

Printer communication may now be carried on between the stations, signals sent by keyboard contacts I6 being repeated by relay 6 and those sent by keyboard contacts 9 being repeated by relay 4.

The operation of the single line repeater for repeating neutral signals may be clearly seen from the drawing. For example, the positive impulses originating at I6 operate relay 6 so as to open line l, the holding circuit for relay 4, however, being maintained from positive battery through the make-before-break contact of relay 5 to ground. For a complete description of the operation of such a single line repeater reierence is made to the patent to G. S. Vernam et al., No. 1,895,015 issued on January 24:, 1933.

Removal of plug i5 from jack 2 will reconnect line 3 to negative battery through line relay l. Polar relay 5 will operate to engage its front contact, thereby reconnecting line 'I toy negative battery. Polar relay lil will disengage its back contact removing the shunt from winding of relay I I, which will operate and then its contacts thereby stopping motor I2. The circuit will then be restored to its normal idle condition.

In the idle condition, momentary depression of Y break key i8 will open line 7, releasing relay 4 which will in turn open line 3, causing deenergization of line relay l. When released, one pair of contacts of this relay short circuit the line winding, preventing it from operating upon reclosure of the line. The other contacts light calling lamp 9 through an obvious circuit. This lighted' lamp serves as an indication at the central station that the outlying station is calling. To establish communication, the procedure outlined above shall be followed, merely inserting plug l 5 in jack 2.

A somewhat different arrangement is necessary ior providing a similar reverse current control through a repeater interconnecting outlying stations when a normally low value reverse current is maintained for the purpose of automatic switching.

Fig. 2 illustrates an arrangement of a repeater in accordance with my invention applied to an automatic telegraph switching` system such as disclosed in the patent to G. S. Vernam No. 1,895,113,

patented January 24, 1933. In this arrangement a printer station designated generally at 300 is connected' through a repeater 205 and a switching means itil to a central printer apparatus designated generally at 550. In this arrangement, at the central station is provided a printer 50' cong trolled by a polar relay 5I, a calling dial 52 and a three-position key 53. Normally current from positive battery flows through the lower winding of re1ay5l while the other upper winding is connected from ground through upper contact of key element 55, printer contacts and resistance 58 to battery. Relay 5l is differentially wound and the` current through the lower winding is normally about half that through the upper winding.. Negativecurrent is impressed on the line through the selective switching means from battery 57 through the lower contact of switch element 54. From selective vswitching means 450 run two lines 40 and 4l. In the normal idle condition, lines 40 and 4| are not selected and consequently relay 42 is notenergized. A negative battery is connected through the winding of slow release relay 43, back contact of relay 42 to a line 2), over line 20, through winding of relay 22, contact of relay 23, and windings of relays 24 and 25 to ground. Relays 23 and 24 are the repeating relays, similar to relays ll and 6 of Fig. l; each of these relays,

however, has an additional winding. Relay 25' 21 through line 2i to the station set 300, through the upper slow resistance and lower high resistance windings of polar relay 30, the lower contact 3l of key 34 and the printer apparatus to ground. Current through relay 30 holds it operated thus maintaining the printer motor 35 at rest.

If communication between the main station 500 and the subscribers station 300 is desired', the operator at central station 500 dials the number corresponding to the station 300. If the station is not busy the selective switching means 400 establishes a circuit, operating relay 42. Operation of relay 42 switches line 25 to the upper contact connected withI line l l, extending positive battery from station 560 through the line connection to line 20. This reversal of current over line 20 causes polar relay 25 to move its armature against its back Contact, thereby extending positive bat- Y tery over line 20 to the station set. Simultaneously the pesitivebattery now connected to theY ar- Y,

mature of relay 25 will cause polar'relay 28 to The operation of relay 2'! short circuits the lower high resistance winding of polar relay 25. Positive kbattery is now extended over line 2l and since resista-nce 26Y has been short circuited this battery is strong enough to cause the operationof relays at station 300. Positive current through relay winding 30 causes pelar relay 30 to make its backV contact, energizingV relay 3,6 over a circuit extending'from power supply through the winding of relay 2E, the oli-normal contact of dial 31,1oack contact of relay 38, armature of relay 30'to the other side of the power supply. Energization of relay 36 closes the circuit of printer motor 35, causing it to operate. Intercommunication may nowbe carried on between station 300 and central station 500, the repeating relays 23 and'24r Operation of relay 22 causes its front contact to make, short circuiting resistance 26.

operating as single line repeaters for the printer signals. Y

When rcommunication is terminated the operator at the central station operates a release key, releasing the selective switching means. Release of this switching means releases relay 42, connecting line 20 through winding of relay 43` to negative battery. This negative battery extending to the repeater operates relays 25, causing it to disengage itsback contact and to engage its front contact, therebyV connecting negative battery again to line 2| and tothe station'. set.

Negative battery at the station set operates relay 30, causingritA to open its contact, stopping'the printer motor at this set. Polar relay'28 also disengages its back contact, releasing relays 22 and 2l',V and engages its front contact, reestablishing the circuit for the added windings of relays 23 and 24, holding theserelays in the operated position. The circuit is now restored to its normal idle condition. V

To initiate a call from the station 3070 to the central station 500, calling key 34 is operated to its calling position, to the right as shown inthe drawing', closing the upper contact 3l and opening its lower contact. This operates to short circuit the' lower high resistance winding of polar relay 3l), increasing the current in line 2l. The increase in current in line 2l is suiiicient to operatev relay 2l, which closes its contact, short circuiting the high resistance winding of polar relay 25. The short circuiting of the high resistance winding of relay 25 causes an increase in the current in line 2li, causing line relay t3 to operate. Relay 43 starts the idle selector switches, causing the line finder to switch the call through to` central station 56d. When the line iinder switch has connected line 2! to an idle selector circuit, a current strong enough to operate relay 22 will cause a short circuiting of resistor 26, in turn increasing the current in line 2l so that the dial lamp at that station will light. Dial 3l may then be operated to select the desired class of service in a manner such as disclosed in Patenty 1,895,113. These dial pulses will be repeated by relay 23 to line 2Q. If no selecting circuit is idle at the time the line finder switch connects tol line 2li, the current in line 2D will not be suiilcient to operate relay 22 and resitor 25 will not be short circuited. The current in line 2l will therefore not increase suiiiciently to light the dial lamp at the station set. When a connection is nnally establishedv through the switching unit, positive battery will extend from the station 5GB over line 2i! as previously explained, anc? will condition the circuit for intercommunication and start the printer motor at station set B as fully described above. Since my invention relates only lto the repeater circuit, a complete description of the operation of the system illustrated in the station set 390 and the switching means at central stations Mlil and 5%, has not been set forth in detail. For a more complete description of the operation of this part of the system, reference may be had to the description in the patent to G. S. Vernam, No. 1,895,113.

While I have described the reverse current control in connection with Figs. l and 2 for the use of starting and stopping printer motors, it is clear that the reverse current may be used for selective signaling, or other purposes. When used for selective signaling the polar relays at the station set may be used to operate single stroke bells instead of printer motors. My invention relates primarily to the repeater circuit for repeating these reverse current signals regardless of the use that is made thereof at the printer station.

While only two specic embodiments of my invention have been described in connection with the accompanying drawing, it should be distinctly understood that these speciiic arrangements are described merely by way of illustration and not as a limitation on the scope of the invention. What I consider as my invention and desire to secure protection on is deiined in the appended claims.

I claim:

1. A single line telegraph repeater comprising means for repeating message signals composed of current impulses of one polarity and break intervals of no current and means for repeating reverse current impulses, said last named means comprising a means responsive to the polarity of applied signals and a contact means controlled thereby.

2. A single line telegraph repeater comprising line controlled relays controlling make-break contacts for repeating signals composed of elements comprising current impulses of one polarity and no current periods, and a polar controlled relay controlling a potential reversing means for repeating reverse polarity signals.

3. A telegraph system comprising a first station, a second station, a single transmission line f interconnecting said stations, means for transmitting signals composed of impulses 0I" one polarity no current spaces, a repeater in said transmission line between said stations for repeating said signals, means for transmitting signals of a reverse polarity with respect to said one polarity to said repeater from said stations, and means in said repeater responsive to said reverse polarity signals for repeating said reverse polarity signals from said station transmitting said signals to said other station.

4f. A single line telegraph repeater comprising a line section, a second line section, neutral line relays in said rst and second line sections, repeating contacts in each line section controlled by the line relay the other line section for remake-break signals from one line section to the other, means for normally maintaining a current of a fixed polarity on said second line section, means responsive to reversal of po- 6. A telegraph repeater comprising a rst line section, a neutral line relay in said first line section, a second line section, a neutral line relay in said second line section, front contact means in each of said line sections controlled by the relay in the other line section, back contact means operative upon opening of said front contact means, to complete a holding circuit for the line relay in the corresponding line section, means for applying a potential to said rst line section, means for reversing the potential applied to said first line section, and means controlled by the polarity applied to said iirst line section for applying a holding potential of the same polarity to said back contacts.

'7. A telegraph repeater according to claim 6 further comprising means for reversing the polarity on said second line section in response to the reversal of polarity on said rst line section.

8. A telegraph repeater according to claim 6,'

in which said last named means comprises a polar relay connected to said iirst line section and a circuit controlled by said polar relay.

9. In a telegraph system, a iirst line, a second line, a repeater connected between said first and second lines, means' at said repeater for normally maintaining a potential of fixed polarity on said iirst line, means for normally maintaining a potential of a fixed polarity on said second line, means for reversing the polarity of the potential applied to said rst line, and means at said repeater responsive to the said reversal of polarity for correspondingly reversing the polarity of the potential applied to said second line.

l0. A telegraph repeater comprising a rst line section, a second line section, separate line relays in each of said line sections, contacts in each line section controlled by the line relay in the other line section, holding windings on said line relays, means normally maintaining a holding potential on said holding windings, means for normally maintaining a potential of a xed polarity on said second line section, means responsive to reversal of the potential on said `iirst line section for reversing the potential on said second line section and other means responsive to said reversal of potential for releasing said holding potential from said holding windings.

1l. In a printer telegraph system, a central station, a subscribers station, a repeater, a first transmission linev interconnecting said central station and said repeater, a second transmission line interconnecting said repeater and said subscribers station, means at said repeater for normally maintaining a potential of a xed polarity on said second transmission line, means at said central station for normally maintaining a potential of the same polarity on said first transmission line, a separate line relay at said repeater in each of said transmission lines', a contact in each of said transmission lines controlled by the relay in the other transmission line, means at s'aid subscribers station for transmitting call signals through said repeater to said central station, means at said central station for indicating said call signals, means for applying a potential of a reverse polarity on said first transmission line in response to an answer to said call signals and means at said repeater responsive to said reversal of polarity for reversing the polarity of the potential applied to said second line section. Y

12. In a printer telegraph system according to claim 11, a selective switching means at said central stations, and means' responsive to said call signals for connecting said subscribers line to said central station, said means for applying reverse polarity comprising means responsive to said line connection for connecting a reverse polarity source to said line.

13.k In a printer telegraph system, a central station, a subscribers station, a repeater, a rst transmission line interconnecting said central station and said repeater, a second transmission line interconnecting said repeater and said subscribers station, means at said repeater for normally maintaining a potential of a fixed polarity on said second transmission line, means at said central station for normally maintaining a potential of the same polarity on said rst transmission line, a separate line relay at said repeater in each of said transmission lines, a contact in each of said transmission lines controlled by the relay in the other transmission line, means at said central station for applying a reverse polarity on said iirst transmission line, means at said repeater responsive to said reversal of polarity for reversing the polarityof the potential applied to said second line, and means at said subscribers station responsive to saidk potential reversal for rendering operative said subscribers' printing apparatus.

14. In a printer telegraph system, a central station, a subscribers station,.a repeater, a rst transmission line interconnecting said central station and said repeater, a second transmission line interconnecting said repeater and'said subscribers station, means at said repeater for normally maintaining a potential of a xed polarity on said second transmission line, means' at said central station for normally maintaining a potential of the same polarity on said rst transmission line, a separate line relay at said repeater in each of said transmission lines, a contact in each of said transmission lines controlled by the relay -in the other transmissionV line, means at said subscribers stationV for transmitting call signals through said repeater to said centralistation, means for applying a potential of a reverse Y polarity on said transmission line in response to an answer to said call signals, and means at said repeater responsive to reversal Yof `polarity for reversing the polarity of the potential applied to said second line section.

FREDERICK G. HALLDEN.