US2095415A - Telephone and printing telegraph signaling system - Google Patents

Description

Oct. 12, 1937. E. E. KLEINSCHMIDT TELEPHONE AND PRINTING TELEGRAPH SIGNALING SYSTEM Filed April 14, 1954 'INVENTOR E'DWAPDE/IZE/NJCHM/DT Patented Qct. 12, 1937 r 2 95 415 .fuN r-Eo STATES PATET eerie TELEPHONE AND PRINTING TELEGRAPH SIGNALING SYSTEM Edward E. Kleinsehmidt, Highland Park, 111., as-

signer to Teletype Corporation, Chicago, 111., a corporation of Delaware AppIication April 14, 1934, Serial No. 720,557

2ev Claims. (01. 179-3) {This' invention pertains to combined telegraph telephone equipment will not respond to the cirand telephone systems and more particularly to cuit of the ground contact at the substation either a signaling system wherein either telephone or because itiis unresponsive to such a circuit or be telegraph service over a common signaling chanse t e Cen a @5108 fi p q p 5 nel is selectively available. 7 Spends more quickly or interferes with any re- 5 Central switching oflices for interconnection sponse by the central ofiice telephone equipment. of telephone lines serving telephone substations t e telephohetubstfition q pment, the

are an established feature of telephone service. 11001; Switch Op in W -known manner to- Central concentration and distributing stations Complete a loop circuit p n the line Wir sand.

10' for receivingand forwarding telegraph messages an t a Contact flpelated y the ook switch 170,

are widely usedand further central OfilCSS or level. removes a grou 0011116651011 from ato central switchboards for interconnecting telek y Of the telegraph Set. At the telegraph graph" lines servingtele'graph substations are Substation quip n a calling k y i p vided usedto serve an increasing volume of telegraphic fi (tonne-Sting a ound Contact to one of the trafiic. Toprovide for economicaluse of line e W es a d in response t the p cf 15 wires for therendering of telegraph and telethe k y a contact in the eleph ne d e Wiring phone service to'substations which do not dcs pened. so t he ph ne hook switch is mand continuous tel'ephoneand telegraph service, disabled o Co ple g 9} 10013 Circuit 1113011 the a single signaling channel may be used for tele line wires and further inresponse to the operagraph service and for telephone service seleotiGYl 0f the e aph Ca key a substitute 2o tively. H ground contact for the telegraph calling key is The principal object of the invention accord- Provided, us rendering the telegraph S deingiy is provide i bl and inexpendent of the ground contact at the telephone pensivesignaling system wherein either telet W ich Co t y be Operated at y time phone or telegraphic communication may be 'by the telephone hook lever. Thus, Whichever of 215.

establishedonfa signaling channel common therethctWO s at oh equ pments is taken into use to to the-exclusion of the other. Wi l disable the other. 7

A featureof the invention is'the provision of At c Central O fi a buSy-bytest condition mechanism responsive at both the subscribers s provided which is standard and well known 0 station and the central office upon the selection a a busyyes on i n f r utomatic teleof the system 'for one type of service for renphone equ pment switching; namely, a ground dering the system incapable of being used for contact upon the private wire of a telephone line the other type of service until the system is q p The private Wir s f h tw q ip- 'res'tored to its normal unactuated condition. ments; telephonic and telegraphic, at the cenconnecting telephone and telegraph substation ith the result that a buSY-bsr-test ground conequipments to a pair of line wires in such mannection upon either private wire renders the nor that either, when in use, disables the other, other private wire and its equipment also busy and by connecting telephone and telegraph cenby test. Equipment is provided at the central tral office 'equiprnents to'thepair of line wires in office to operate inresponse to the telephone sub- 40 such manner that either, when in use, disables station loop signal to connect the calling substa the other'fthe central office telegraphic equiption to a manual jack and to illuminate a signal ment being solely responsive to the substation lamp to attract the attention of a telephone optelegraphic equipment and the central offioe te1eorator. Equipment is provided to operate in rephone equipment being solely responsive to the sponse to the ground contact of the substation 45 substation telephone equipment. telegraph calling key to search and to seize a The central 7 office telephone equipment prorecording telegraph receiver which then becomes vided will respond to a loop circuit formed by responsive to the telegraph transmitter at the the usual hook switch. of a substation telephone, calling station.

the central oflice telegraphic equipment however A better understanding of the'invention'may 5o will'not'respond to a loop circuit. likewise, the be had from the following description, taken in central office telegraphic equipment will respond conjunction with the accompanying drawing, I to a circuit formed by a ground contact placed wherein a single figure shows a telegraph and upon a line'wire by a calling key at the substatelephone substationinterconnected to a central tiontelegraph equipment, but the central ofllcc omce equipped. for both telephonic and tele- 55 The above and other objects are attained tral ofilce are connected together permanently 35 V graphic communication. In the drawing, many of the parts or units have been designated by general reference numerals; for example, at the subscribers station, numeral I indicates a telegraph substation equipment, 2 a telephone set, and at the central ofiice, 3 a line switch and its operating and controlling relays, 4 a manual switching unit for responding to set 2 and switch 3, while 5 indicates a manual switching equipment for calling set 2 by a manual operator, and 6 indicates an automatic switch for calling set 2 by control of a remote operator. Likewise, 1 indicates a line switch and its relays and 8 a recording telegraph receiver for responding to set I and switch I, while 9 indicates a manual switching equipment for connecting and transmitting to set I by a manual operator and I8 indicates an automatic switch for communicating with set I by control of a remote operator.

Telegraphic equipments I, 8, 9, and lll are connected over line wire II to telegraphic substation :I where a telegraph receiver magnet I2, transmitter I3, and motor I4 comprise the customary telegraph equipment to which is added a slow-to-release relay I5, 2. series condenser 56 and ringing relay I'i responsive to alternating current from the central office, a relay I3 responsive to a power source which may be of alternating or direct current, and a calling key 58 having a latch 25 and a polarized magnet 2i whose armature operates the latch 2d against the urge of its retractile spring. Motor M has a centrifugal switch 24 shunted by resistor 25, the switch 24 operating to close contacts only during the period when the motor I4 is operating at proper speed for telegraphic transmission. Contacts of relay I8 shunt transmitter contacts I3 to prevent interference by contacts I3 in the progress of setting up a connection. Relay i5, which is included serially in the communication circuit during the operation of the telegraph substation, has its winding shunted by a noninductive resistor 27 to reduce the inductance of the communication circuit, and has five pairs of armature contacts of which contacts 28 are included in the communication circuit, contacts 29 control the operation of the motor I4, contacts 35 connect ground to line wire "44, contacts 3i connect a substitute ground to provide against interference with telegraphic service by opening of the contact 33 at the telephone hook switch, and contacts 32 open the telephone bridge wires. A source of electrical power is provided upon wires 3 and 35.

In telephone substation 2, a transmitter 52 and a receiver 4i are in series with contacts of hook switch 453 and contacts 32 of relay I5 to provide a telephone bridge upon line wires I l and i when the hook switch is operated into its upward position. A telephone ringer 45 and series condenser 46 are connected from ground through contact 33 and contact 32 to line wire 44.

At the central ofiice, an equipment 3 for receiving a telephone call originating at substation 2 comprises a non-numerical automatic line switch comprising a set of brushes 59 and a plurality of sets of bank contacts 55, the brushes being driven by a motor magnet 52 in cooperation with a line relay 53 and a cut-off relay 5d, the relays 53 and 54 having a mechanical interlocking device which permits the cut-off relay to break all back contacts without closing any front contacts if the line relay is found deenergized at the time that the cut-off relay becomes energized, but should the line relay be found energized at the time that the cut-off relay becomes energized, the cut-oif relay will move its armature a full stroke. The operation of this nonnumerical switch and the relays mentioned is described in Automatic Telephony by Smith and Campbell, 2nd edition, 1921, pages 51 and 52.

The bank contacts 5| are connected to jack 6!], line relay BI and local relay 62, the line relay BI having contacts connected to battery and to signal lamp 63, and local relay 62 having contacts connected to ground and to private wire 64. A manual telephone operator, in response to illumination of lamp 63, may connect with jack 60 by means of plug 65, thereby cutting off relays 6! and 62 and connecting the line wires II and 44 to apparatus not shown, but by which telephone service may be given to the substation 2 in response to an originating call.

To the standard equipment of the non-numerical switch just described there are added relays l8 and H, the relay 70 having its front contacts connected to shunt corresponding back contacts in. relay 54 so that circuits may be preserved when both relays 54 and IE3 are energized, and reiay I! having its winding differentially connected so that it is not energized in response to loop circuit upon line wires II and 44 but is responsive to a grounded circuit over line wire ii whereby current flows over line wire II without corresponding current flowing over line wire 44.

A line switch equipment forming a part of the telegraphic switching equipment I comprises a non-numerical switch such as is shown in the equipment 3, with the exception that only one brush and contact is used in the communication circuit. Communication brush I2 and private brush I3 are driven by motor magnet 14 in cooperation with line relay l5 and cut-off relay 16 which have interlocking features corresponding to relays 53 and 54. Bank contacts and 8| are connected to contacts of connector relay 82, local relay 83 and release relay 84. A telegraphic recorder which may be a printer or a reperforator or both is provided and is indicated by its selector magnet 85 and details are shown further by a set of permutation bars 86, a selector pull bar 87, a power bail 89, and a pair of contacts 8B operable by the pull bar 81 and operating to close a circuit to energize the release relay 84.

The operation of the system in response to calls originating at the substation is as follows.

For telephone service: The user of the telephone set 2 may take control of the line wires II and 44 by lifting the receiver 4|, thereby operating hook switch 43 which at once disables the telegraphic substation I by opening the contact 33, thereby removing from the telegraphic substation I the ground connection which is required to enable the substation I to initiate control of any central office apparatus. Neither can the operator at the telegraphic apparatus I control the relay l5 to open contact 32 to interfere with the telephone circuits about to be described, so that by closing hook switch 43 when the substation equipment I is inert, the telephone station 2 has seized the line wires II and 44 and has removed any possibility of interruption from the telegraphic equipment connected thereto at the substation. The closing of the hook switch 43 has closed and electrified a circuit beginning at the central ofiice through battery, line relay 53, contacts and lower winding of relay II, contacts of relay 54, line wire 44, contacts 32, hook tacts 51 and operates relay 54 fully, which trans-.

switch 43, receiver 4|, transmitter 40, line wire II, contacts of relay 54, upper Winding and contacts of relay II toground. Relay H is not ener'gized because" of its differential nature. Relay 53 is energized andthe resultant operation of the non-numerical switch connects brushes 5!! to-confers the line circuit described from relay 53- to relay 6|, energizingrelay BI which in turn energizes relay 62 overan obvious circuit. Relay 62 connects ground to private wire. 84 thus forming a holding circuit for relay 54,- and relay 8I illuminates lamp 63 overan obvious circuit. The

manualoperator responds by inserting plug 65 in jack 60 thereby completing another holding circuit for relay 54 to ground connectionupon the plug 55. Contacts of jack 60 open the circuit of used for telephonic communication byoperating V the manual key It whose latchZO-retains the contacts of the .key in operated position. A telegraph calling circuit is formed beginning at central office battery, through winding; of relay 53, contacts and lower winding of relay II, contacts of relay 54, line wire 44, third and fourth contacts f of operated key l9, hook switch contact 33 and ground. Current now flows through but one winding of relay II and energization is effected in relay II and relay 53 but the operation of relay II disconnects the relay 53 and substitutes a circuitfrom battery over wire 89'and thencethrough the lower winding of relay 1|. Contacts of relay II also: open the upper winding-of relay 1| and atfurther contact of relay II' closes a circuit to energize relay I5. The, circuit of relay I5: extends from battery, through contacts of relay I6, contacts of relay I I, contacts of deenergized relay 54, line wire II, selector magnet'IZ, contacts of energizedrelay I8, resistor 25, winding of relay I5, lowest two contacts of key I9, winding of.magnet 2|, and contact 33 to ground. The polar direction of the current is such that it is ineffective upon polar magnet 2|. By. reason of resistor 25, the volume of current is too small to be eifective upon selector l2. Relay I5 at the substation and relay 'I-5 at the centraloffice are operated. In response to relay 15, the non-numerical switch connects brush 12 to contact and brush I3 to contact BI. Operationof relay I5 opens contacts 32 whichdisables the telephone set 2, closes contact 3 I, which substitutes a ground connection for the: ground connection of contact 33, closes contacts 29 which start. the motor 14 into operation,and closes contact 28 which shunts the connection between fifth and sixth contacts of operated key I9 to maintain a-communication circuit after release and restoration of key I9; Operation of the non-numerical switch of equipment I energizes relay 16- to openits back contacts and transfers the circuit from winding: of relay I5 to the winding of connector relay 82, the

new circuit extending from, battery through contact of deenergized relay84, winding of relay- 82,-

contact of relay 8 2, bank contact '88, brush 12,

for relaylfi, and at the same time connects ground tothe windingof relay 82 to form a holding circuit for relay 82. The armature contacts of relay 82 remove the winding of relay 82 from the circuit of the line wire II and from the definitive central oflice' communication circuit as follows: frombattery 80, through winding of receiver selector magnet 85, contacts of operated relay 82,'bank contact 88, brush 12,'contacts of relay I6, line wire II, selector magnet I2 of home recorder or station I, contacts of energized relay I8, resistor 25,resist or 21, contacts 28 of energized jrelay I5, windingof polarized magnet 2|,

and contacts 3| ofenergized relay l5 to ground. All batteries which have been considered heretofore as supplying current to line wire I I have been of uniform polarity and of such polarity that polarized magnet 2| has not attracted its armature in response to any current, but battery 98 is of reversed polarity, to which polarized magnet 2| responds, attracting its armature 28, releasing key I9 anddeenergizing relay I8 which opens its contacts toremove the shunt from the contacts of transmitter I3; Motor I4 has attained full speed and closes its centrifugal contacts, thus shunting resistor 25- and reducing the resistance of the communication circuit to produce'in cooperation with battery 98 ajproper volume of operating current in the communication circuit. Theoper'ator at-station I, noticing the releaseof his starting key I9, then may operate his transmitter I3 to record upon the selector indicated by magnet 85at the central oflice the message which he desires to transmit.

During the interval of use of the line wire II for telegraphic service, the-telephone substation is disabled by thecontact 32 and the telephone central oflice equipmentis disabled by a busy-bytest condition placed upon private wire 9| at first by the middle contact of relay I5, later by the lower contact of relay 83, effecting operation to median position of thearmatures of relay 54. Wire 9| extends to test contacts of equipments 9 and III to prevent access to the line by telegraph operators, extends to the test conductors of equipments 5 and 6 to prevent accessto the line by" telephone operators, and thus guards the line at the central ofiice to secure to the operator at station I the exclusive use of the line for telegraphic purposes on his originating message.

Having completed transmission of a message, 7

the'operator at station I transmits a predetermined signal such as fblank code in response to which-the code bars 86 permit the pull bar 81 to operate and-to be operated to closethe elec trical contact 88 which energizes release relay "84 over an obvious circuit, the relay 82 being energized at all times throughout the communication period. Relay 84 opens the circuit of the ,winding of relay 82 and deenergizes relay 82,

retains relay I8 fully operated and relay 54 par-' tially operated, and the open condition of the circuit of linewire II is continued for a periodof time: sufficientto effect the release of the slowto-release relay l5 at substation I, which opens the circuit of the motor and restores all of the apparatus of substation I to its normal inert-condition, The final act of the cycleis the release of the armatures of relay 84, which removes busyby-test condition from line wire 9|, deenergizes relays 54 and I6, and restores battery connection to the winding of relay 82 and thus to bank contact 80, which restores all central ofiice apparatus to normal inert conditions.

Outward service For telephone service: Telephone service in which the central office calls the telephone substation 2 is efiected by inserting the manual plug I00 into the manual jack IIII and ringing with the manual key I02. The insertion of the plug in the jack places ground upon private wire 9| and operates cut-off relays 54 and I6 to middle position of their armatures, thus preventing the operation of equipments 3 and I. It also places the busy-by-test ground condition upon all manual jacks and automatic switches through which the line wires II and 44 might be taken for service. Ringing current from alternating generator I93 through key I92, plug I00, and jack IIJI passes over line wire 44 and through contact 32, ringer 45, condenser 46 and contact 33 to ground. During the period from the time of seizing the line by inserting plug I09 in jack IIII to the time of response of the attendant at telephone station 2, the attendant at telephone station I may operate the key I9 to initiate a telegraph message, but there will be no response by the telegraph switching equipment I since cut-01f relay T6 is operated, and the attendant at telegraph station I will be unable to proceed with the transmission of a telegraph message because the relay I5 will not be energized and the motor I4 will not start into operation. Since the relay I5 cannot be energized, its contact 32 cannot be opened and the telegraph substation I cannot interfere with the response of the telephone substation 2. Telephone operators situated remotely from jack IIJI may obtain communication with telephone set 2 through automatic connector switch 6, see Smith and Campbell's book, Fig. 60.

For telegraph service: There is provided at the central ofiice a manual jack I I 0 connected to the line wire II and to the private wire 9|, and a manual switching plug III having an individual ringing relay H2 and an individual ringing condenser I I 3 through which it is associated with a common alternating current ringing generator II4, having also a receiver recorder indicated by the selector magnet H5 and individual transmitter I I6 and an individual key I IT by which the plug may be associated with a common testing telephone II8.

In operation when it is desired to send a telegraph message to substation I, the manual operator inserts plug III in jack III] and thus sets up a combined ringing circuit and battery response circuit as follows: from ground through ringing generator II 4 and condenser II3, contacts of relay II2, key In, plug III, jack IIO, line wire II, selector magnet I2, condenser I6, relay II, fifth and fourth contacts of key I9, and hook switch contact 33 to ground. Relay I1 responds and closes its contacts which permit battery current to flow through the battery response circuit, from reversed battery I20, through transmitter I I6, selector magnet I I5, upper winding of relay II2, choke coil I2I, key II'I, plug III, jack IIil, line wire II, selector magnet I2, transmitter I3, resistor 25, winding of relay I5, contact of relay I'I, fifth and fourth contacts of key I9, hook switch contact 39 to ground. This current energizes relay I5 which closes its contacts 28 to shunt the contacts of relay I'I, its contacts 29 to start motor I4 into operation, its contacts 3| to substitute ground for the ground of hook switch contact 33, and opens its contacts 32 to disable the telephone set. Motor I4 attains operating speed and closes its centrifugal switch 24 which shunts the resistor 25 and in creases the current in the circuit last traced to a volume which energizes relay II2 to operate and to form the definitive transmission circuit as follows: reversed battery I20, transmitter IIG, selector magnet II5, contact of energized relay II2, key II'I, plug III, jack III], line wire II, selector magnet I2, transmitter I3, switch 24, resistor 21, contact 28 of relay I5, fifth and fourth contacts of key I9, contact 3| of relay I5 and ground.

The central oifice operator then transmits the desired message by means of transmitter II 6 and record is made at substation receiver I2. The central office operator is unable to transmit until substation motor I4 has attained operating speed, thereby increasing the current in the communication circuit to operate relay I I2. By the insertion of plug III in jack III], the ground upon the plug placed a busy-by-test condition upon private wire 9|, operating both relays 54 and it to armature mid-position, and guarding the line against intrusion by any central office apparatus of either telephone or telegraph nature.

Also, by the insertion of plug III in jack IIEI and the operation to mid-position of relays 54 and it, the response of central office switching apparatus to telephone hook switch 43 was rendered impossible and the instantaneous response of relays IT and then I5 had opened contact 32 to disable the telephone set at once.

Automatic switching for outward service: Operators situated remotely from jack IIII may attain connection with the line wire I I and telegraph set I by manual trunking to similar jacks or by automatic trunking through an automatic connector switch I2I for telegraph service. The connector switch is of the type described on page 59 in Smith and Campbells book identified above,

and the relay I22 in the drawing is the wiper closing relay which is energized following a busy test of the line and which remains closed during the then ensuing connection. Other details of equipment I0 are identical with the details of equipment 9.

It will be seen that the system above described constituting one embodiment of the present invention provides equipment for a single communication line of two conductors such that telegraph messages originating at the substation and extending to the central office or further and conversely, telegraphic messages originating in the central office or more remote parts and terminating in the substation I may be served by the telegraph equipment on the line wires II and 44 over the line wires II and 44 without interference from any possible operation of telephonic apparatus, either substation or central ofiice, after the line wires I I and 44 have been taken for telegraphic purposes; also that the line wires I I and. 44 may be taken for telephonic service by the substation equipment 2 or by any one of the equipments 3, 5, and 6 to provide telephone service over the line wires II and 44 in either direction and without the possibility of interference by any telegraphic equipment associated with the line after the moment when the line wires are taken for telephone service. There is complete independence in the two services given bythe two sets of equipment .upon the line wires and 411, with the feature that the line wires may be taken at any point of access for either class of service to the exclusion of all service of either-class which may attemptto use the line.

and telegraph switching .arts, it is possible to construct widely variant systems to accomplish the. results attained in the embodiment here shown: Therefore, although the invention has 7 been described in connection with a specific form thereoflit will .beunderstood that it has further applications andit is not intended to be limited in scope by. the embodiment shown herein for illustration; i

What is claimed is: l 1. In a system for rendering telegraph and telephone service .over a single signaling channel, a station having a telegraph set and a telephone set, a distant station, a signalingchannel connecting said stations, a relay. .at said distant station connected tosaid channel while said-;.ch,annel,is idle and responsive to control over said channel by said telegraph set, and neutralizing means in said relay rendering said relay unresponsive to control by said telephone set. a

, 2.In' a system for rendering. telegraph .and

. telephone service pver asingle: signaling chan- 'neLasWitching'statiOn, a substation having a 3,; In afsystem, for telegraph and telephone service-over ,a single pair of line wires, a switching station, a substation having telegraph :and telephone sets, a line connecting said stations, a. first relay at said switching station energizable over said line by one of said sets, and-a. second relay at said switching station energizable over said line under control of the other of said sets alternatively with'the energization of said first relay by its energizing set and operating whe energized to disable said first relay.

4; In a system for rendering telephone service and telegraph service over a single pair of line wires, a switching station, a substation having a telegraph set and a telephone set, a line connecting said stations, a telephone line relay at said switching stationand responsive to control over said line by said telephone set or'said telegraph set, and a fast to operate line relay at said switching station responsive to control over said line by said telegraph set for. disabling said telephone line relay.. a

5. In. a system for rendering telephone service and telegraph service over a single pair of line wires: a switching station, apparatus sets for telegraph and telephone respectively, a line connecting said stations, a firstline relay at said switching station and connected to said line when idle and responsive to control .over said'line by one of saidsets, and a secondline relay at said switchingstation and connected to said line when idle and responsive to control over said'line by natively when said line isidle 6. In a system for rendering telephone service and telegraph service, a, signaling channel, a

telephone substation connected to said channel, a telegraph substation connected to said channel, a central ofiice line switch connected to said channel responsive to said telegraph substation, a further central office line switch connected to said channel responsive to: said telephone substation, .and switching means at the central cfiice for connecting with said channel and for signaling either of: said substations and when connected rendering both of said central oflice line switches inoperative.

.7. Inv asystem. for rendering telephone service and telegraph service, a line, a telephone substation connected to said line, a telegraph substation connected to said line, a central oflice line switch and cut-ofi relay connected to'said line responsive to-said telegraph substation, a

further central oflice line switch and cut-'ofi relay connected to said line responsive to said tele- 7 phone substation, and switching means at the central ofiice for connecting with said line and for signaling one of said substations and when connected energizing both of said cut-off relays and rendering both of said line switches inoperative.

8. In a. system for rendering telephone service and telegraph service, a. line, a telephone substation connectedto said line, a telegraph substation connected to said line, first means at a central office responsive to said telegraph substation toinitiate a switching operation and to render said line busy by test, second 'means at said central ofiice and responsive to said telephone substation to initiate a switching operation and to render said line busy by test, and further means at said central oifice operable when said line is not busy by test for connecting with said line and for signalingone of said substations and when connected rendering both of said firstmeans and second means inoperative and for rendering said line busy by test. a 1 r a 9. In a system for the combined working of telephone and telegraph apparatus, a telegraph substation equipment, a telephone substation equipment, a telegraph central office switching equipment, a telephone .central ofiice switching equipment, a line connecting said telegraph substation equipment, said telephone substation equipment, said telegraph central oflice switching equipment, and said telephone central ofiice switching equipment, a ground-return circuit through said telegraphcentral ofiice switching equipment, said telegraph substation equipment and said line when idle over which said telegraph central omce switching equipment is responsive to control by said telegraph substation equipment, and a. loop circuit through said telephone central oifice switching equipment, said line when idle and said telephone substation equipment over which said telephone central ofiice switching equipment is responsive to control by said; telephone substation equipment. -10. In a system of combined telephone and telegraph apparatus, a telegraph substation equipment, a telephone substation equipment, means in said telephone. substation equipment for disabling said telegraph substation equipment when. said telephone. substation equipment is taken for service,,meansin saidtelegraph substation equipment for'disabling said telephone common to said telephone substation equipment and said telegraph substation equipment, a central oflice telegraph line switch connected to said line andresponsive to control by said telegraph substation equipment, a central ofiice telephone line switch connected to said line and responsive tocontrol by said telephone substation equipment, means in said central ofiice telegraph line switch for disabling said central office telephone line switch when said central oifice telegraph line switch is taken for service, and means in said central office telephone line switch for disabling said central oiiice telegraph line switch when said central oflice telephone line switch is taken for service, said two means comprising in part two cut-oiT relays, a test wire for busy-by-test condition and common to both of said cut-01f relays.

11. In a system of combined telephone and telegraph apparatus, a telegraph substation equipment, a telephone substation equipment, means in said telephone substation equipment for disabling said telegraph substation equipment when said telephone substation equipment is taken for service, means in said telegraph substation equipment for disabling said telephone substation equipment when said telegraph substation equipment is taken for service, a line common to said telephone substation equipment and said telegraph substation equipment, a central ofiice line switch responsive to control over said line by said telegraph substation equipment, and a further central oiiice line switch responsive to control over said line by said telephone substation equipment, both said line switch and said further line switch connected to said line at all times when said line is not in use.

12. In a system of combined telephone and telegraph apparatus, a telegraph substation equipment, a telephone substation equipment, means in said telephone substation equipment for disabling said telegraph substation equipment when said telephone substation equipment is taken for service, means in said telegraph substation equipment for disabling said telephone substation equipment when said telegraph substation equipment is taken for service, a line common to said telephone substation equipment and said telegraph substation equipment, central ofiice apparatus responsive to control of said telegraph substation equipment, and alternative central office apparatus responsive to control by said telephone substation equipment, both said line switch and said further line switch connected to said line at all times when said line is not in use.

13. In a signaling system, a plurality of stations, telegraph and telephone units at each station, a signaling channel connecting the stations and connected to the telegraph and telephone units, seizing means at each unit for seizing said channel for service, means responsive to the seizure of the signaling channel by the said seizing means of either unit at any station for rendering the said seizing means of the other unit at the same station non-effective, and means operative upon the seizure of the signaling channel for either type of service for establishing a communicative relationship with the corresponding type of apparatus at a distant station.

14. In a combined telegraph and telephone system, circuits and apparatus for the dual operation of a telegraph set and a telephone set over the same line circuit connecting a subscriber station with a central office, comprisinga switching system connected to said line circuit and responsive to the telephone set, a further switching system connected to said line circuit and re-. sponsive to the telegraph set, line circuit seizing means in each set, means to disable the line circuit seizing means of the telephone set when the telegraph set is in use, means to disable the line circuit seizing means of the telegraph set when the telephone set is in use, and means lo cated at the central oflice to place a busy-bytesl condition on both switching systems when either the telephone set or the telegraph set is in use.

15. Circuits and'apparatus for rendering telegraph and telephone service over a single signaling channel comprising a subscriber station having a telegraph set and a telephone set, a central station, a signaling channel connecting said stations, and a relay at said central station having a single winding normally in circuit with both the telegraph and the telephone sets and responsive to control over said channel by said telegraph set and having windings differentially connected in series with said telephone set.

16. Circuits and apparatus for rendering telegraph and telephone service over a single signaling channel, a central switching station, a subscribers substation having a telegraph set and a telephone set, a signaling channel connecting said stations, a differential relay at said switching station responsively connected to control over said signaling channel by said telegraph set and difierentially connected to control by said telephone set, and a further relay responsive to control over said line by said telephone set.

17. Circuits and apparatus for rendering telegraph and telephone service over a single signaling channel, comprising a central switching station, a subscribers substation having a telegraph set and a telephone set, a line connecting said stations, a first relay in said switching station energizable over said line by said sets, and a comparatively faster energizing relay at said switching station and responsive over said line under control of one of said sets, to disable said first relay.

18. Circuits and apparatus for rendering telephone service and telegraph service comprising a switching station, a substation having a telegraph set and a telephone set, a line connecting said stations, a telephone line relay at said switching station responsive to control over said line by said telephone set, and another relay at said switching station responsive to control over said line by said telegraph set to energize simultaneously with said telephone line relay and adapted to disable said telephone line relay.

19. Circuits and apparatus for rendering telephone and telegraph service, comprising a central station equipped with two individual sets of switching apparatus, one for the telegraph and one for the telephone, apparatus sets for telegraph and telephone, located at a subscriber's station, a line circuit connecting said stations, a line relay at said central station controlled over said line by either of said telegraph or telephone sets, and a second line relay responsive to control over said line by one of said sets, one of said relays having operating precedence when both are simultaneously energized.

20. Circuits and apparatus for carrying out the dual operation of telephone and telegraph over a two wire and ground extension from a subscriber station to a central station, characterized in that the telephone message circuit is over a metallic loop and the telegraph message circuit is over one of the'two wires to ground, and means for rendering the telephone and telegraph inoperative when the other is in use, com-- prising a switch in the telephone circuit located at subscribers station which is automatically operated when the telegraph is in use to disable the telephone and a further switch in the tele- -graph circuit located at the subscriber station which is automatically operated when the telephone is in use to disable .the telegraph.

21. Circuits and apparatus for carrying out the dual operation of telephone and telegraph over a two wire and ground extension from a central toa subscriber station characterized in that the telephone calling circuit is over a metallic loop and the telegraph is over a grounded loop, and a r system of relays is included in both calling circuits and located at the central station to select the telephone switching apparatus and render the telegraph inoperative, selectively in response to closing the telephone calling circuit.

22. In a system for the alternative working of telephone and telegraph apparatus, a substation,

a central ofiice, a connecting signaling line, substation equipment of two classes including means for producing calling signals of two different electrical natures over said line, and central office call responsive means comprising two automatic switches and a system of relays connected to said line when said line is in condition of readiness for seizure for service and responsive to a. signal received over said line to select one of said automatic switches according to the nature of the received signal. 23. In a system for the combined operation of telephone and telegraph apparatus, a substation, two preselectors, for telegraph and telephone communication respectively, a. line connecting said substation and said preselectors, and'means at said substation for causing selectively a response of either of said preselectors by control over said linej EDWARD E. KLEINSCI-IMIDT.

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