US1843228A - Radio telephone and telegraph circuits - Google Patents

Description

2 Sheets-Sheet l k.) INVENTORS ATTORNEY J. HERMAN ET AL RADIO TELEPHONE. AND TELEGRAPH CIRCUITS Filed Feb. 5. 1929 Feb. 2, 1932.

Feb. 2, 1932. .1. HERMAN ET AL 1,843,228

RADIO TELEPHONE AND TELEGRAPH CIRCUITS ZIE . 2, Camif/'00 Raw/7@ 'r @gg v INVENToRs .Igel/Www, EzyZa/f @L Wsw@ , ATTORNEY Patented Feb. 2, 1932 UNIT-E srarns vrarenr orricn kJOSEPH HERMAN, OE wEsTEiEEn, NEW JERSEY, EDMUND n. TAYLOR, OE NEW YORK, N. Y., AND sUMNEnnwnien'r, OE souri-I onsite-E, NEw JEnsEY, nssrenons ro AMEnrcAN TELEPHONE AND Tanne-nnen contraria?, A conronn'rron or NEW lYORK RAD TELEPHONE .AND TELEGRLH CIRCUITS yllqiplication filed February 5, i829. Serial No. 837,616.

Vtelegraph messages over a radio telephone channel. p

' ln o1 eratin' aradio tele yhone circuit such Vas the transatlantic system between the United States and Great Britain it is desirable to transmit iniormation for setting up telephone callsby means of yprinting telegraphy. A irinter is also desirablei'for sending information between technical employees having` charge of themaintenance of the circuit. In accordance with the present invention, circuit arrangements are provided 'whereby printer messages may be transmitted Vduring times that the radio link is not being employed for telephone transmission.

As is well lnowina radio transmitter and radi-o receiver may' be connected by means of a four-wire circuit at Rocky Point, Long island, and the receiver at Houlton, iti-aine, while the switching point is in New York City. 'The'our-wire circuit compri es two two-wire lines extending from New Yori City to Rocky Point and froulton, respectively. ln the ciiice at N ew Yorlr City, acontrol room is provided whereby a technical operator has control ot the terminal amplifiers, voice-operated devices, privacy mechanism and other apparatus associated with the lfour-wire circuit. The two-wire terminal of the four-wire circuit passes through the control room to an operating roomA where it terminates upon a ack so that the trar''ic operator may establish connections to other telephone circuits. ln accordance with the invention, printing apparatus is provided beth in the controlv room and in the operating room, so that either the technical operator '.orthetratiic Operator, atone end of the system, can communicate Vwith the correspond- Ving loperators at the other end.A

Since the trahie operator is not ordinarily trained lto operate aV printer, and more-over,

co a two-wire terminal at afswitching ypoint where connections are estabished between the'radio channel and various telephone circuits. Forexample, in f H5 vthe transatlantic radio telephone system above kreferred' to, ythe radio transmitter` is located duties in connection with the establishi 'nt of connections which make it undesirafto burden her with printer operation, the

printer in the Operating room is operated by a printer operator who is located near the traiic operator, so that information relating io calis may be readily passed by the trailic operator to the printer' operator for transmission over the circuit.

ne printing equipment in both control and .sing rooms consists of two units, one of l is a combined sending and receiving iter, and the oher of which is a receiv- `die two rooms y are connected serially in a loop, and likewise, the combined sending and receiving printer units of the two rooms are connected in another loop. The receiving "nter units are used when the system is opf ed on a full duplex basis with signals ,v sent in both directions at the same time.

ns, is used as a home recorder for recording tl e transmitted message. When operating on a half duplex basis, so that signals are transmitted only in one direction at a given time, the receiving printer unit is not used, but the combined sending and receiving unit is used for both sending and receiving in the local loop.

In the control room, the two loops are associated with a voice frequency carrier arrangement soY that the printer messages may be sent and received over the four-wire circuit of the radio system by means of an audible tone. rlhe receiving carrier channel is permanently bridged across the receiving path of the four-wire circuit between the radio receiver and the echo suppressor disabling device, so lthat it is always in condition to receive printer messages without any switching operation. The transmitting channel of the voice frequency carrier apparatus, on the other hand, i arranged to terminate in the operating room in a jack before the switchboard operator in the same manner that telephone lines terminate, so that the sending printer may bc connected to the twopath is disabled, the circuit is in condition 'to receive telegraphmessages.' Means are also provided whereby, when the sending wire terminal vot the tour-wire system by means of the operators cord circuit.

Arrangements are provided so that when the sending printer vis connected to the twowire terminal of the tour-wire system bythe cord circuit, the voice-'operated echo suppressor equipment is automatically set to render the transmitting path of the four-wire circuit operative'to transmit signals to the radio" transmitter. The receiving path is at the same time disabled, but as thel carrier telegraph channel is connectedther'eto between the radio receiver and the point atv which the printer is Connected to the four-wire circuit, the Oain ot the amplifier in the transmitting path is automaticallysetatthe desired value Y tor printer transmission.

Supervisory signals are provided whereby Y th'eprinter operator in the control room may signal the trafiicloperatorto setup 'or take down the printer connection and whereby the jtrahfic operator may signal the printer operator that the connection isset up. lMonitorfing means are also provided so that the trahie operator may monitor the circuit. `The cir- VVVcuit isalso so arranged that when the tratiic operator desiresto use'the radio link for telephone purposes, the sending printer may be disconnected andra signalV will be given* to the Aprinteroperator to indicate that i'act.

Tn :the control room, the technical operator .is provided with means whereby the printer located in that room may be connected to the two-wire terminal ot the tour-wire circuit the Aprinter operator when the printer iscongiie'ctezd. to the circuit. Y v The inventionma-y now ,be more derstood trom the following description Y fully unwhen read in connection with the accompanyiing drawings, Figures l and 2 of which show the circuitv arrangement for one terminal of a radio telephone system kembodying the invention, and F ig; 8 of which shows a modification ofv the voicejfrequency carrier telegraph apparatus employed in connection with the system.

YReferring tothe drawingaFigs. l and 2 showvr the circuit yarrangement of a four-wire terminating arrangemeiitat one end of a radeley circuit DR.

dio telephone system, the radio` transmitter and receiver, however, being not illustrated. It will be understood, of course, that the arrangement at the distant terminal of the radio telephone system will ybejsiiiiilar'to that illustrated. In consideringthedrawingsnt should be noted that the portion of the circuit shown in Fig. 2 is the apparatus associated with the, Y

four-wire circuit leading to the radio transmitterand receiver rointhe two-wire terminahwhile the apparatus shown in Fig. l comprises printers and associated circuit arrangements ior connecting them with the four-wire circuit.v lt should alsobe noted that all ofthe apparatus to the lett ot the vertical dotted line in Fig. l is apparatus located inthe operating room 'where the traffic operator sets up telephoneand printer connections ywith the radio system. The apparatus to the right of the dotted line in Fig. l

cal operator has supervisory'control Jfor the purpose otl maintaining thek apparatus in proper operating condition.

Referring to Fig. 2, L designates the twowire terminal of the tour-wire circuit interconnecting the radiov transmitter and radio lreceiveratone end of a radio telephone sys- The two-wire terminal L is connected tem. through a hybrid coil 10 to a transmitting path TL Aand receiving path RL, the terminal L being vbalanced by asuitable network 3N. The pathv TL includes ainpliiiers TA and .TA and a delay circuit- DT. Beyond these Y elements the pathv TL isV associated bym'eans .of al hybrid coilll with-the privacy mechaynism PM,.oie well-lmown form, which performs the function ofrendering speech transmitted therethrough unintelligible. Atterpassing'throiigh the privacy mechanism PM,

the transmitting path continuesfover'theline TL including the amplifier "',to the distant radio transmitter.

The receiving path RL', incoming from .the radio receiver, is connected to the neuj tral points of the hybrid `coil l1. Since the Y privacy mechanism PM is balanced by a network PN', the connection of the receiving path RL to the hybrid coil renders such path conjugate withV respect to the transmitting path The receiving path, after passing through vthe privacy mechanism PM, continues over the circuit RL which includes receivingzamplifiers RA and RA, as well as Inv order that when transmission is taking Vplace over either the transmitting orreceiving path, the other path willbe disabled,

echo suppressor devices are associatedwith veach path.v The echo Ysuppressor equipment associated with the transmitterl path TL comprises an amplifier-detector unit TAD, orwell-knownV type, bridged across the path .TL on the output side of the amplifier TA.

v 1185 and the apparatus indicated in Fig. 2 will be .located in the control room where the techni- The output of the amplifier-detector unit TAD controls-through master relay 20 the relays'12,.13, 1d and 15 for performing the switching operation incident to the blocking .or disabling operations ivhereby telephone transmission is permitted only in one direction at a time. Normally, both sections TL and TL of the transmitting path are disabled by the back contacts ot' relays 12 and 13 which short-circuit the conductors. Since vthese tivo sections of the transmitting path are interconnected through the privacy mechanism PM, and the two short circuits are applied on opposite sides of the privacy mechanism, .transmission from the section TL to the sectionk TL cannot normally'talre place `through the privacy mechanism. Blocking means,y ycomprising transformer arrangements 16-17 and 18-19, are associated with .the receiving path sections RL and RL, re-

spectively. These disabling means comprise .transformer arrangements which are so connected as to be balanced when the contacts ofV relays 14 and 15 are opened, thereby preventing transmission through the trans former arrangements. When the contacts of relays 14 and 15 are closed, however, the

transformer circuits, instead ot being balanced lare in eitectconnected so as to be ar- 7. u LL. u n allel aiding, thereby permitting transmission f to rtake place readily. Normally, relays 14 l and 15y (which are controlled by the aniplitierdetector TAD)Y are deenergized, so thatl the receiving path is unblocked to permit transmission to take place from the ra- .dio receiverA through the privacy mechanism v'to the terminal of the Wire circuit L. An

I amplifier-detector arrangement RAD is conscribed for telephone transmission is as follows :V Telephone currents incoming'over the tivo-Wire circuit L pass through the hybrid coil and through the amplifier TA. Some Vof the energy enters the amplifier-detector unit TAD and causes the relays 12, 13, 14 and to be energized. Relays 12 and 13 remove the short circuits from the transmitting sections TLr and TL', While relays 14 and 15, byopening their contacts, cause the inission of the telephone currents until these operations have taken place, fitter Which the telephone currents pass through the amplithe telephone operation of the circuit.

fier TA through the hybrid coil 11, thence through the privacy mechanism PM and then out through the amplifier TA and over the line section TL to the radio transmitter. The amplifier-detector RAD associated With the receiving path cannot be actuated to disturb the circuit condition now existing, because the receiving path is disabled in the manner already described.

It, in the normal condition of the circuit,

t lephone signals are received over the line section RL from the radio receiver, they pass through the amplifier RA and the transformer arrangements 16-17 to the midpoints of the hybrid coil 11 and thence through the privacy mechanism PM, through the ampliiier RA and through the vtransformer arrangements 18-19. Sonie of the received energy actuates the amplitier-detector RAD to cause the operation oi the relay 20 which opens the circuit controlled by the ampliiier-detector unit TAD, thereby preventing energization of relays 12, 13, 14; and 15, so thatthe transmitting path is maintained disabled and the receiving path remains unblocked so long as telephone currents are being received. Tn the meantime, the telephone currents aie delayed in passing through the delay network DR until the foi'eooineo erations take lace after Whichb El 7 the telephone currents pass through the receiving amplifier RA to the niidpoints ot the iybrid coil 10 and thence to the two-Wire terminal L.

The apparatus so tar described relates to The printing telegraph equipment, and the circuits whereby it is associated With the four- Wire telephone circuit leading to the radio transmitter and receiver, will nowbe described. Referring to F ig. 1, it Will be seen that the tivo-Wire terminal of the telephone circuit passes through the control room and terminates in a jack J in the operating room,

whereby it may be connected through a cord;

circuit GC to jacks, such as TJ, associated with telephone lines, such as L, for complet ing connections to telephone subscribers. At the sufitchboard of the traffic operator (which includes the jacks of various telephone lines such as TJ) is a jack TCJ which is connected over a circuit TCL to the transmitting equipment of a voice frequency carrier telegraph apparatus shoivn Within the dotted rectangle at The circuit may therefore be connected by the trailic operator through the cord circuit C to the two-wire terminal L of the tour-Wire telephone circuit to connect to the circuit the Iending equipment or the printing apparatus hereinafter described.

The printer apparatus located in the operating room for sending and receiving printer messages necessary tor'the establishment of telephone connections bythe traiiic operator,

comprises two units, a `combined'transmitting and receiving unit conventionally indiwhereby the printer operator may signal the 'traic'operator when a connection to the -radio circuit `is desired. Y

--Siniilar printer equipment is located in the control room i'or the use of the t-echnicaloperator 'in sending messages relating` to the 'maintenance and operation ot the circuits.

.This equipment comprises a combined transmitting and'receiving unit TP anda unit RP. which comprises a receiving printer only. The receiver units RP and RP, in the operating: and control rooms, respectively, are connected in series in a receiving loop RPL.

The sending and receiving' halves of the combined'printers TP and TP in the operating .and control rooms, respectively, are arranged in'series with each other, andthe two units are also connected Vin series in a loop TPL,

s'othat wheiia sender of the unit TP, for

example, is operated, the associated receiving printer of that unit will operate as a Vhome recorder, and also the receiving portion vof the'unit Tl? will'record the same rnes- Y sage inthe control room. vLikewise, when record the 'messageLl -inay be associated with the set'TP for' tape the Vsender ot the unit TP is actuated, the receivingelement's of both yprinter units will A. tap-e transmitter TS sending. g

.The voice `frequency carrierapparatus at X is shown connected tor'a full duplex operation so that transmission may take .place in both directions simultaneously. VThis carrier apparatus comprises a. transmitting` relay TR associated with the transmitting loop TPL and having its varmature arranged to short-.circuit the output Vci oscillator O, which Vgenerates va tone frequency vwhich will be interrupted in accordance with the transmitted printer signals, and transmitted through the transformer 30 and over thercircuit TCL and two-wireterminal'l/ to the transmitting path of the'tour-wire circuit. The receiving1 portion ot' the voice frequencyv carrierequipnient comprises a receiving relay RR for transmit-tine the printer code tothe loop RPL. The relay Rit-is controlled by an amthe voice frequency carrier equipment is per- -inanently associated with the receiving secalhier-detector unit D for am lit ine` and rectif in@ the received tone ltrom the distant -f transmitter. The',amplifier-detector Al) of tion RL of the four-wire circuit over a cirvcuit whichvincludes an amplifier RCAv Hhaving ahigh impedance input, so that the connection' of the circuit RCL to `the receiving' path RLadoesfnot introduce any material loss for telephone transmission over the Apath RLT-RL. A iilter RCF fory selecting the tone employed in transmitting from the distant station may also bel included between tfnleD circuit RCL-'and the amplifier-detector A f The printer apparatus in thecontrol room may also include a' tape sender TS connected in series with the transmitting keyboard of the transmitting unit TPV', so that control room messages may be punched on the tape and allowed to accumulate until the technical operator has an opportunity to obtain control oi' the radio circuit for printer transmission. The` printer apparatus in the control room hasassociated therewith a signal 29 for indicating when the sending apparatus of the control 4room printer isconnected to the twowire terminal L. Such vconnection may be established independently of theftrafflc 0peiator by fnieans of an ordinary patching cord PC which .will interconnect jacks CBJ and CBJ', the one associated with the sending printer and the other associated with the tivo-wire terminal L. vWhen the patching connection is made, the transmitting side ot the voice frequencycarrier apparatus is disconnected irom the circuit TCL leading to the-tratlicoperators board and is connected to the jack CBJ. 1 r

The traihc operators cord circuit CC for .establishing telephone connections orsending printer connections, includes the usual supervisory signal 27, splitting'key SK and monitering and talking key TMK the latter, when ,thrown to the left,fbridging the operators receiverl OR kacross the cord, and, when thrown to the'right, connecting both the operators transniitterOT and receiver OR to a tone sourceinay be connected to the cord i circuit for signaling the traicoperator at the distant end.. The tratc operator is also `provided with a lamp 25 to indicate signals transmitted by the printer operators key BSK when theprinteroperator requests the circuit. The traliic operator is also provided with a key BLK by which lshe can cause the printer operators lamp 28 to flash to indicate that thetraific operator wants the circuit Jor a telephone connection. The traiiic operator also has at herboard a jack MJ, byk

means Yof which she may monitor on the re- Y ceiving printer circuit RCL, a lamp 27 being provided to indicate to the traflic operator that the printer circuit is set up so that she should monitor. A y

A polar relay PR is bridged across the two-- wire terminal L; ilVhen operated, this relay f performs three functions'. Itsets the poten-y tiometer of the amplifier TA in the transmitting path. It operates therelays 12, '13, 14 and l5, to disable the receiving pathy and cut ging into the jack MJ with another cord circuit, and'throwing a monitoring key. Another circuit is established throughthe relay K whichy shortcircuits the sending apparatus of the'control room printing set TP to prevent the 'sending' of printersignals Jfrom this set. A third circuitl is established over the back contact of relay H to the lamp Q8 associated withthe printing apparatus lin the ing marginal, was not; energized over the sleevecircuit, and hence thesupervisory ref lay U or the cord was permitted to close the circuit of the supervisory lamp 26. As soon as relay C is energized, ground is connected over its upper 'front contact lto short-circuit the 'resistance r, thereby increasing the'cur'r rent iiow over the sleeve circuit through the relay l) and theVv relay M, causing the latter to be energiZed,-thereby opening theV circuit of thesupervisory relay U andextinguishing the lamp 27 to notify the traific yoperator that the printer operator has taken'control of the circuit. p

The energization of relay H bythe locking keyRSK, as previously described, opens the circuit previously traced'for the printer operators lamp 28, but this circuit is reestablished at the same time over the front contact of the relay G which is now operated. Consequently, the lamp 28 glows as long as the sending circuit is established :tor the printer. Vihen the sending apparatus of the `printer unit TP is operated to 'transmit printer sig- ,r nals, the loop TPL is interrupted to cause current and' no-current intervals in accordance with the printer code. The receiving' apparatus of the printer units TP and TP record the messagev thus transmitted. At the same time, the transmitting relay TR Aor the voice frequency carrier equipment is energire'dland kdeenergized in accordance with the ycede' to cause an interrupted toneki'rom the `'oscillator Oto be transmitted through the transformer 30 and over the circuit TCL, cord circuit lCC and two-wire terminal to the .hybrid Vcoilof vthe four-wire circuit. AFrein the hybrid coil, the teneis transmittedv over the circuit TL through the ley-pass about thc privacy mechanismPM, and over the circuit TL to the radio transmitter. At thek same time, ot course,printer signals from the dis'- t-ant station may be received through the amplitier-detectorfAD and recorded Von the receiving printer units RP and RP in the manner previously described. Consequently,

printing may taire place inboth directions at the same time. i Y 1 Operation when z/ie printer operator Tegueste a Y j the ycircuit a,

TI". the printer operator desires to use the radio telephone apparatus ata time that it is being used 'for voice transmission, she operates the request service key BSK, causing the operation or relay H as before. Relay il, at its lower front contact, completes a circuitthrough the relay G, outer back left-hand contact or" relay E, back contact of relay D and through the windingA of relay A to batf tery. The operationot relay A causes the line lamp 25 associated with the jack TCJ to glow, thereby indicating to the traffic operator that the circuit is requested. -When the trahie operator establishes connection from the circuit TCL tothe two-wire terminal L by means oi the cord circuit CC, the operation of the relay Din the sleeve circuit releases .relay A and extinguishes the line lamp. 'The other relays operate as previously described, except that in this inst-ance the relay C is operated by the relay D as soonv as the operator plugs into thejaclr TG5, so that the marginal relay M at once operates and vpr-eventsthe actuation ot the signal lamp 27 by the supervisory relay U. Y Printing now taires place as already described. i Y Release of the radio telephone circuit lf the traffic operator desires to use vthe radio telephone circuit for telephone transmission Vwithout Waiting for the completion of a printer message, shepulls down the cord CC connected to the telegraph circuit TCL. This causes therelease of the polari, relay PR associated with the two-wire circuit L,.there by restoring' the four-wire circuit to normal condition, with the transmitting path disabled and the receiving path-in normal talk# ing condition. The relay F associated with thevoice frequency carrier equipment is also released at the saine time, thereby eXtinguishing the monitoring lamp 27 and the service lamp 28 at the printer. The printer operator at once kno-ws that the circuit hasy been takenvaway and simply waits until the circuit. is re-established, which -tact will be indicated by the lamp 28 vagain glowing. II", however, the printer operator no longer desires to use the circuit, the request'rservice lrey RSKis restored and the circuit returns to normal. ,l n

It the traiiic operator wishes tovuse the cir` cuit for telephone transmission but iswilling to wait until a telegraph message, then being sent, is completed, sheV operates the request line key BLK at her position. lThisconnects interrupted `ground over the contacts of said operate and release. VEach timeV the relay B operates, it establishes an alternate path for fill BSK, thereby releasing relays G and C.

The latter relay removes the short-circuit from the resistance 1", thereby causing the marginal relay M to release. Consequently,

r the supervisory lamp 27 again glows, giving the traliic operator the signal to disconnect the sending printer circuit; The operator accordingly pulls down the cord' and restores the circuit to normal.

Olonnecz'oa to printer circuit at control board Y It, the attendants in the control room Wish to' use the radio telephone circuit for printer operation without involving the traliic operator, the technical operator connects the iack CBJ at'the control board to the jack CBJv of the two-wire circuit L by means of an ordinary three-conductor patching cord PC. Ground is connected over the sleeve of this cord to operate the relay E. lRelay E transfers the output connection of the transformer 30 from the circuit TCLvto the jack CBJ, thus establishing a direct connection to the two-wire circuit L. Relay F and polar relay PR are new operated, the latter performing the functions previously described. Relay F, however', connects vground over its front contact and makes contact of the outer right board sender of the printer unit TP may be operated to send messages, it preferred. The

short-circuit previously described as being established over the Contact of relay l does not now exist. It is, of course, obvious that the sending printer TP might be used for sending signals over the circuit thus established.y but the operator of such a printer would not do so, as the lamp 28 would not glow to indicate to such operator that the printer circuit was established.

Half (Zaple opera-tion The telegraph operations above described were on a full duplex basis, that is, telegraph messages were transmitted from both directions at the same time. vhere the circuit is to be operated o-n a halt duplex basis, so that transmission can take place in both directions, but only in one direction at a time, the voice frequency carrier apparatus will have its circuit modified as shown in Fig. 8. Under these conditions, the receiving loop RCL is disconnected from the voice frequency carrier apparatus, `and the armature oi' the receiving relay RR is connected to the neutral point of the transmitting relay TR. llfhen the receiving relay RR is receiving printer signals, positive and negative batteries are alternately connected to the midpoint of the relaj,T TR, thereby causing current and nocurrent intervals in the transmitting loop TPL Without actuating the transmitting relay TR. Acordingly, the receiving elements of the printer units TP and TP are operated to record the received message. Under these conditions, the receiving printer units BP and RP are not used. lVhen it is desired to transmit from the printer unit TP, for example, the sending apparatus is operated to open and close the loep TPL. This causes the receiving elements et the units TP and TP to record the message transmitted. At the same time, the transmitting relay TR is operated. to send an interrupted tone from the oscillator C in the manner-previously described or full duplex operation.

It will be obvious that the general principles herein disclosed may be embodied' in many other organizations widely different from those illustrated, Without departing from the spirit of the invention as detined in the following claims.

` l.What is claimed is:

l. ln a radio telegraph system, a four-wire circuit comprising a transmitting path and a receiving path i''or connecting a radiotransmitter and radio receiver, respectively, to a two-wire terminal, a telegraph transmitter and telegraph receiver, means for continuously maintaining said telegraph receiver in connection with said receiving path, and means to connect said telegraph transmitter to said two-wire terminal at will.

2. In a radio telegraph system, a four-wire circuit comprising a transmitting path and a receiving path for connecting a radio transmitter and radio receiver, respectively, to a two-wire terminal, a telegraph transmitter and telegraph receiver, a voice frequency carrier apparatus associated with said telegraph transmitter and receiver, said apparatus comprising means to translate a received tone into telegraph signals for said telegraph receiver and means to transmit a tone varied in accordancewith signals 'from said telegraph transmitter, means to maintain said translating means in continuous connection with said receiving path, and means to connect said tone transmitter to said two-wire terminal at will.

lll)

3. ln a radio telegraph system, a vfour-.wire circuit comprisinga transmitting path and a receiving path rorrconnecting a radio transmitter and a radio receiver, respectively, to a two-wire circuit, an operating room and a controlroom through whichsaid two-wire circuitpasses, atelegraph transmitter and telegraph receiver in ysaid operating room, a

telegraph transmitter and telegraph receiver' in said controlroom, means to maintain said telegraph receivers in continuous connection with said receiving path, and means to connect either telegraph.transmitteryto said twowire circuit atwill.

4. In a radio telephone and telegraph sysmission takes place over the other, a telegraph transmitter and atelegraph receiver, means to maintain saidtelegraph.receiver continually in connection with said receivingv path beyond the point at which it is disabled, means to connect said telegraph transmitter to said two-wire terminal at will, and means responsive to suchconnection to operate said voice-controlled means independently of vocalr transmission to render said transmitting path continuously operative whilethe connection is established. Y 5.l In a radio telephone and telegraph system, a tour-wire circuit comprisingV aftransmitting path and a receiving path for connecting a radio transmitter `and a radio receiver, respectively, to a two-wireterminal, meansto establish telephoneconnections to said two-wire terminal, voice-operated means associated with said tour-wire circuit iFor disabling one ci its paths when telephone transmission takes place over the other, a telegraph transmitter and a telegraph receiver, a

voice frequency carrier apparatus associated with said telegraph transmitter and receiver, said apparatus'comprising means to translate a received tono into telegraph signals for said telegraph receiver and means to transmit a tone varied in'accordance with `signals from said telegraph transmitter.` means to lmaintain said translating means in continuous connection with said receiving. path beyond the .point at which it is disabled, meanst'o connect said tone transmitter tosaid two-wire terminal at will, and means responsive to such connection to operate said voice-controlled means independently of vocal transmission to render said transmitting path continuously operative while the connection is established.

A 6. In a radio telephone and telegraph system, a tour-wire circuit' comprising a transmitting path and a receiving path for conreceiver in said operating room, a telegraph transmitter and telegraph receiver insaid control room, means to maintain said telegraph receivers continuously connected to said receiving path beyond the point at which it is disabled, means to connect either telegraph transmitter to said two-wire circuit at. will, and meansV responsive to'such connection yto operate said voice-controlled meansfindependently of vocal transmission to render said transmitting path continuously operative while the connection is established.- Y V '7. In a signaling system, a transmission vcircuit adapted to transmit either telephone or telegraph signals and terminating at a switching position, a telegraph instrument having a circuitV terminating at said switching position, a telephone line terminating' at said switchingv position, means vat said switching position whereby a traffic operator may connect said telegraph instrument or said telephone line to saidy transmission circuit a't'will, and means operative when the telegraph instrument lisV disconnected Jfrom the transmission circuit whereby the telegraph operator may indicate to the traiiic Voperator that a connection 'is desired. v Y

l 8. ln a `signaling system,y -a transmission circuit adapted to transmit either telephone or telegraph signals and terminating at a switching position, a telegraph instrument having a circuit terminating at said switching position, a telephone line terminating at said switching positiommeans at said switching'v Aposition whereby a traiiic operator may connect said telegraph instrument or said telephone line to said transmission circuit at will, and means independent oi' the operators telegraph instrument to indicate to the telegraph Voperator that the telegraph instrument has been connected at the switching position. l l

9. In a signaling system, a transmission circuit adapted to transmit either telephone or telegraph signals and terminating at a Vswitching position, a telegraph instrument link circuit to indicate to the traiic operator that the telegraph operator desires the connection between the telegraph instrument and the transmission circuit taken down.

l0. In a signaling system, a transmission circuit adapted to transmit either telephone or telegraph signals and terminating at a switching position, a telegraph instrument having a circuit terminating at said switching position, a telephone line terminating at said switching position, means at said switching position whereby a traiiic operator may connect said telegraph instrument or said telephone line to said transmission circuit at will, means operative when the telegraph instrument is disconnected from the transmission circuit whereby the telegraph operator may indicate to the trailic operator that a connection is desired, means independent of the operators telegraph instrument to indicate to the telegraph operator that the telegraph instrument has been connected at the switching position, and means at the switching position to indicate to the traiic operator that the telegraph operator desires the connections taken down.

11. In a signaling system, a transmission circuit adapted to transmit either telephone or telegraph signals and terminating at a switching position, a telegraph instrument having a circuit terminating at said switching position, a telephone line terminating at said switching position, means at said switching position whereby a traiiic operator may connect said telegraph instrument or said telephone line to said transmission circuit at will, and means independent of the operators telegraph instrument to indicate to the telegraph operator during the continuance of an established connection from the telegraph instrument to the transmission circuit that the trattic operator desires to take down the connection.

12. In a radio telephone and telegraph system, a four-wire circuit comprising a transmitting path and a receiving path Jfor connecting a radio transmitter and a radio receiver, respectively, to a two-wire terminal, means to establish telephone connections to said two-wire terminal, voice-operated means associated with said four-wire circuit for disabling one of its paths when telephone transmission takes place over the other, an amplier in said transmission path, a privacy mechanism associated with said four-wire circuit for rendering speech unintelligible, a telegraph transmitter and a telegraph receiver, means to maintain said telegraph receiver continuously in connection with said receiving path beyond the point at which it is disabled, means to connect said telegraph transmitter to said two-wire terminal at will, means responsive to such connection to set the gain of said amplifier at a predetermined level, to cut out said privacy mechanism, and

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