Патент USA US3033939код для вставки
United States Patent Ollice 1 3,033,929 TELEGRAPH HUB REPEATER CIRCUÍT .lames T. Neiswinter, Garden City, NY., assigner, by ~ 3,033,929 Patented May s, 1962 2 point of +15, to a swing of +43 to +39 at the base of T3 which has a mid-point of +2. This centers the swing around approximately +2 volts lon the emitter of T3 and mesne assignments, to The Pioneer Electric 8; Re results in no bias to transmission -from the send hub search Corporation, Forest Park, Ill., a corporation through T3. of Illinois . n ~ ’ With the send hub at +60 corresponding to a mark Filed Nov. 10, 1959, Ser. No. 852,106 signal voltage, and the voltage on the base of T3 at +43, T3 will be non-conducting. Under this condition, the current Ithrough the windings of «the send relay will be The present invention relates to an improved telegraph l0 approximately seven mils, as determined by +130 volts repeater unit and more particularly to a transistor-ized cir through R18 to the windings. Since the resistance of cuit which is a direct plug-in replacement for existing the windings of the relay is only 272 ohms, the parallel coupling units in commercial systems of the general type branch of 5.6 K ohms to ground will have little eiîect on disclosed, for example, in U.S. Patent Nos. 2,607,852 to the winding current. The seven mills current will be in Rea and 2,636,942 to Davey. In commercial practice »a marking direction to hold the armature of the relay certain operating conditions and voltages have been stand on mark. i 9 Claims. (Cl. l78-‘73) ardized and are well known to those skilled in lthis art, and the following description will assume an understand .The voltage at the collector of T3 is limited to -24 volts by diode D4. Current will be flowing through R14 ing of this art. and D4 while T3 is non-conducting. The purpose of A principal object of the present invention is to pro 20 diode D4 is to limit the voltage at the collector of tran vide an improved inexpensive, easy to service, direct sistor T3 to a value within the yrating of the transistor. plug-in replacement for prior leg coupling units common Resistor R19 is only for the purpose of protecting the ly referred to as a 144A1 circuit. While the present in transistor at a time when a -24 volt fuse might blow. In vention has essentially the same electrical characteristics this case, with the -24 volts absent, the path to ground viewed externally, because of being a transistorized cir 25 through ‘R19 will limit the vol-tage at the collector of cuit adapted to use three transistors of the `same type, con siderable variation of internal circuitry has been found necessary to provide a practical unit which will comply with the strict testing and exacting standards 4reqin'red in this industry, 30 Referring now 4to the drawing wherein the circuit dia gram of my improved coupling unit is illustrated, the uni-t comprises a receive leg having the usual receive relay with -alternate contacts connected to positive and negative voltages and connected to the receive hub. The send hub is conventionally connected, either directly or through a regenerative repeater 10 by contacts l2 and 14, to the receive hub. The send leg is connected vfrom the send transistor T3 -to -about -26 volts. yIn the idle and in the marking condition of this circuit, all three transistors are non~con2d-ucting~ When the receive hub `goes spacing due to a space being received on another repeater connected to the hub, the lsend hub goes spacing, its voltage becomes _30, and the voltage applied to the base of T3 becomes +39. This causes transistor T3 to conduct and a current of approxi mately 14 milliamps to flow through R14, through tran sistor T3 and the relay windings in a spacing direction to ground. This 14 rnilliamp lspacing current overrides ,the 7 nulli-amp marking current Ifrom +130 volts through R1=8 and causes a resultant current of 7 milliamp 'spacing hub. Varying numbers of from 2 to l0 or more lines which operates the relay to spacing. Thus, any space sig~ are connected to the receive and send hubs, each having 40 nal occurring on the send hub due to a space being re a plug-in unit such as ‘that illustrated in the drawing. ceived from any other repeater on the hub is transmitted With the receive (R) leg of the repeater to which the unit is connected in the mark condition, and the receive and send hubs also in the mark condition, »the voltages at the various points inthe circuit Iare as indicated for con dition “MM.” In these designations, the iirst letter'indi cates the condition of the R leg of the repeater associated with the unit, and the second letter indicates the condition of the R leg of another repeater >connected through a to the send relay directly with no holding action taking place, since transistor T2 is non-conducting under this condition. Y Y. The operation of the receive relay to space of the re peater connected to the R leg of the control circuit (Con dition SM) causesl the voltage on the receive hub to change of +60 to _30. At the same time the voltage on the send hub will change to -30 immediately if there coupling unit to the same receive hub. In the MM lcondi 50 is no regenerative repeater between the receive and send tion, transistor T1 has +22 volts on its base and +8 hubs, or in about halfvavjunit pulse length later if there volts on its emitter and is therefore normally non-con is a regenerative repeater between fthe two hubs. The ducting since no current liows from base to emitter when function of `the control circuit in this case'is to prevent the base is positive with respect to the emitter. .the space voltage on the send hub from operating the 55 Considering transistor T2, the voltage applied to the send relay to spacing and thus sending a space back to base of this transistor results from »the +130 volts through the originator of the space pulse on the receive siderof R4 and R5. This voltage, as applied to the one terminal the circuit. ' of capacitor C1, is limited to +8 volts .by the diode ' When the receive relay -in the lreceive leg of the illus across the collector and emitter of T1. The +8 volts trated circuit goes to spacing, 'the voltage at `the top of on the ungrounded terminal of capacitor C1 is applied 00 R4 changes from +130 to about _120 volts, which directly to the base of T2 through diode D3 which shunts causes a voltage ofabout _22 volts at the junction of R4 resistor R9 for this polarity. TZ is therefore normally and R5. This -22 volts will be applied directly through Inon-cornîlucting, and under this condition will have no diode D2 to capacitor C1 and will change the voltage on effect on the operation of_ T3. rthis capacitor from its MM voltage 'of about +8 to -22 65 Considering transistor T3, with the sen-d hub in the volts for the SM condition. The change in voltage on MM condition, a voltage of +60 is conventionally avail capacitor C1 will take a few nulli-seconds to complete. able ony the send hub and is applied through Rî6 to the However, when the voltage has changed only from +8 base of T3. rllhis voltage is reduced by the -130 volts to +4, transistor T2 will conduct.> The change of voltage applied to the base of T3 through R15. The circuit of this amount takes less than one milli~second. through R15 is for the purpose of changing the +60 to 70 When transistor T2 goes conducting, ythe +5 volts on ‘_30 (the conventional space signal voltage on the send its emitter is applied directly through the emitter-col hub) voltage swing on the `send hub, which has a mid lector path of the transistor and through diode D5 to the . 3,033,929 4 on the occurrence of a double space on the receive hub through 180,000 ohms, the +5 volts will hold the base of sistor T3 from conducting. .. 'Considering the circuit-to the baise of ¿transistor TV1, 4 ' when the voltage of the receive hub was: +60, the voltage A'on the base of T1> was +22, and accordingly transistor T1 was‘non-conducting. When the voltage on the _re ceive-hub goes to -30 for the SMor the MS condition, the voltage at the 'base .of transistor T1 goes to:.+l7 which still leaves transistorV T1 non-conducting.' There. fore, during the SM condition lbeing described, transistorV T1 will remain non-conducting throughout and need not be considered in the holding action .on transistor T3 lunder discussion. >Transistor T1 conducts only under `the SS condition. - ' When the receive relay returns to the marking condi tion it is necessary that the holding etlîect of transistor T2 on transistor T3 remain for nearly the length of a unit pulse. This is ,to provide for the case where regenerative repeater 10 is used betweenthe receive and send hubs, due to two receive legs going spacing atV the same time, the holding action on transistor T3 of the coupling unit is removed andthe space is transmitted through the unit to the associated send line. Since whenv the double space occurs and ltransistor T1 goes conducting, the discharge >of C1 and the change of transistor T2 from conducting to noni-conducting occurs in less Vthan one rnilli-second, thereis practically no delay in the vtransmission of the double space through the unit. »The presence of R17 being connected to the send hub ,is important as it performs two distinct functions. One is »that 'it presents an artificial load to the send hub during Vthe marking condition. Its value is selected so that this load matches the load presented to the send hub during »the spacing condition by the circuit to the base of tran 20 sistor T3. The two loads are not equal in micro-amperes but are of such value that the voltage drop on the send hub is the same for both the mark and space condition. Thus, the addition of a considerable number of legs to the send hub will not cause bias since, with the mar-k and space loads on the send hub balanced for each coupling in which case the space on »the output of the regenerativeV unit, it is comparable to a polar circuit in which decreas repeater will be lagging sometimes nearly a pulse length ing the resistance of the circuit, and correspondingly in behind ,the space on the input when the receive leg signals ’ creasing the current ñow in the circuit does not cause bias because the increase is balanced for the mark and have a large marking bias. It the hold on transistor T3 removed too soon, the last part of this space pulse will -be transmitted to the send line. The `delay in the removal of the hold on the base of transistor T3 is obtained from the circuitry involving space conditions. -conducting. When the receive relay goes to marking, »the positive +130 voltsV that appears at «theriunction of R4 and R5 is blocked by diode D2 and must be` applied to the capacitor through R13 which _has a high value. Transistor T2 Will therefore remain conducting until the voltage on C1 changesfrom _.22 to about +5. The coupling units might be separated from the send hub. This will cause transistor T3 to conduct and send a deñnite 35 space signal to the send line during such a condition, thereby giving a warning to the distant oiiìce that it is cut off the hub. If the send leg did not go open deñnitely under this condition, the distant end might remain _in a closed condition and cut oft' lfrom the hub .for a con siderable time before becoming aware it was no longer on the circuit. values of C1 and of R4 and R5 are selected so that this . Thus, the complete holding action'is that when the lreceive relay goes spacing, the voltage on C1 ,changes quickly from a value of about +8 to the +4 value Without the added current from R17, VVthe amount of base-emitter current in transistor T3 might delay .is approximately one pulse length at sixty speed transmission or 22 nulli-seconds. It is, therefore, ample for H60 w,p.m., and also fior higher speeds which recìuire less y Another function of Ri7 is Vto create more base emitter current in transistor T3' during a time when the capacitor C71. During the SM condition the` voltage on the _capacitor was about Y--22 volts and transistor T2 was delay. . -to spacing to ysend a space onvthe send line .of this re peater. This is called a double-space by-pass action, since ‘ T3 positive even though the send hub is- at +30 volts,'and a conducting condition in transistor'TZ Will’preveut tran-V _ - will thereforego conducting and operate the send relay base of transistor T3. Since this +S volts is applied through only 680 ohms in the »emitter circuit of transistor T2 and since the _30 volts from the send hub is applied be insuiiicient to drive the transistor completely con ducting. The value of R17 is preferably in excess of 5 45 megohms with the voltages indicated in the drawing. Diode D3 is connected around R9 so that when the voltage on capacitor C1 is positive ¿this voltage will he applied to the base of transistor 'T2 through a low re sistance instead of through the resistance of R9 which is »necessary to make transistor T2 conduct, and then con high. This improves the perfor-mance of the transistor tinues on to a value of -22 volts for the steady state 50 considerably at high temperatures since the leakage cur spacing condition. Then when the receive relay returns rent that iìows from collector »to base in the transistor to marking, the voltage` on the capacitor slowly changes during high temperature conditions can not, in its tiow VLfrom -22 volts back to +8, holding transistor T2 con-Y through diodes D3 and D6 and resistors R11 and R10, ducting long enough to allow a space pulse being trans cause' sufficient voltage drop to change the voltage `at the mitted on the send ,leg by a regenerative repeater to vcorn `pletebefore vtransistor T2 is made non~condueting and base of transistor T'Zrfrom a positive to a negative value. Without the diode around R9, the leakage current would the hold onthe base of transistor T3 is removed. create such a voltage drop through this resistor lthat the ,'If, while a space is being received on the receive relay voltage at the base of transistor T2 would become neg and While Clis charged to -22 volts and transistor T2 » ' ative at `fairly low temperatures. When the voltage at is conducting to’hold transistor T3 non-conducting, an 60 the base o-f »transistor T2 becomes negative with respect other repeater associated with the receive hub sends a to the emitter, the transistor will conduct. This would space to the hub (Condition SS)` the voltage on the hub cause a holding action on the base of transistor T3 even will change from --'-30 to -60 volts. This is the so-called 'double-space condition of the hub. ì at times when Vtransistor T2 is intended Ato be non-con ducting.' Signals would therefore be blocked on the Y Y When the receive hub voltage becomes _60, the voltage 65 send leg during times when they were supposed to be applied to the base of transistor Ti becomes -5 and transistor T1 will conduct. During the conducting con dition, of course, the voltage measured at the base of transistor'Tl will be the `same as the emitter voltage 4 which is +8 volts.Y When transistor T1` conducts, it discharges C1 in less than a milli-second and causes the voltage on C1 to be come +8. With the voltage >on C1 equal to +8, tran- Y . unblocked. ' Inhalt duplex` operation, assuming no regenerative re i peater, and a'low capacity hub, the conduction of tran 70 sistor T2 when the receive relay goes spacing must occur before the voltage on the receive and send hubs in com Vbination changes from +60 to +15, which is’the point at which thesend relay goes spacing. This is accom plished by making the charging action on C1 fast so that ' sistor T2 willV go non-conducting and remove the holding voltage from the 'base of transistor T3. Transistor T3 75 it reaches a voltage sutiicient to make transistor T2 con it 3,033,929 duct very quickly. In the case of a very low capacity hub (only one or two legs connected), the voltage on the hub changes to the spacing value quickly enough to p make a slight change in the mark current through the send relay before the hold through transistor T2 is ap plied. This change of current is so slight that the arma ture of the relay does not operate at all and no harm is caused by the slight current kick that occurs. Under the condition of more legs on a hub, the change of voltage on the hub from mark to space will be slower and no cur rent kick on the send relay winding current will be ob served. When a regenerative repeater is used, the ap pearance of the space voltage on the send hub, of course, is delayed usually many milli-seconds and no kick at all will be observed in the send relay winding current.> In the case of full duplex operation, where the voltage on the receive hub changes from _10 volts for mark to -60 volts for space, it is necessary that before the volt age on C1 can change sufficient to cause transistor T2 to conduct and place a hold on transistor T3, that tran sistor T1 be driven conducting to clamp C1 collector at the voltage of +8 which will hold transistor T2' non conducting. This quick action of transistor T1 on full duplex operation is obtained through resistors R6, R7 6 appended claims rather than by the foregoing descrip tion, and all changes which come within the meaning and range of equivalency of the claims are therefore in tended to be embraced therein. What is claimed and described to be secured by United States Letters Patent is: ` `1. A hub telegraph repeater unit of the type adapted to be connected to a receiving hub and a sending hub, said repeater unit comprising: a receiving leg having a receiving relay connected to said receiving hub through an impedance, a sending leg having a sending relay con nected to said sending hub through an impedance and a tirst transistor normally non-conducting to causerthe send ing relay to be in a marking condition; a iirst control stage having a second transistor normally non-conducting when the receiving leg is at rest; circuit means for con necting said second transistor to said first transistor for preventing said iirst transistor from conducting even though a space signal condition is present on said sending hub; means including a resistance, diode and capacitor connected to said receiving leg between said receiving relay and Vsaid impedance for selectively charging said capacitor when said receiving leg has a space signal there on; means for connecting one terminal of said capacitor and R8 and capacitor C2. It should be observed that the 25 to said second transistor to cause said second transistor voltage at the junction of R7 and R8' is about -22 volts when the receive hub is at any value more positive than this, due to the blocking action of diode D7. When a space does occur on the receive hub, and the voltage to control said ñrst transistor and prevent the sending leg from transmitting a space signal; and a second control stage comprising a third transistor; circuit means for connecting said third transistor to said receivingrhub and changes from -10 towards -60, it will change only from 30 to said one terminal of said capacitor for preventing said -10 to -22 before the effect of the voltage change is capacitor from becoming charged when a space signal transmitted through C2 to the base of transistor T1. condition is simultaneously supplied to said receiving hub Therefore, for only a l2 volt change in the voltage on from a plurality of receiving legs. the receive hub, transistor T1 will become conducting and 2. In a hub telegraph repeater unit adapted to be con clamp capacitor C1 at +8 volts. This action will occur nected to a receiving hub and a sending hub, said unit before the voltage change on capacitor C1 due to the cir having a control circuit interconnecting receiving and cuit through Rd has had time to bring the voltage on sending legs for a single circuit for locking and unlock capacitor C1 to the value required to make transistor T2 ing said sending leg in response to signaling conditions conduct. Therefore, on full duplex operation where impressed on said receiving leg comprising a first tran signals on the send side of the circuit must not be inter 40 sistor having base, collector and emitter elements, a first fered with by signals on the receive side, any space pulse circuit means connecting the base element of said first transistor to said sending hub, means for connecting the emitting element of said first transistor to send relay cause no hits to transmission on the send side. ln the windings sending leg and through a >ñrst ini case of added capacity to the receive hub, the change 45 pedance toin asaid source of positive potential whereby the of the voltage from _l0 to -60 on a space will occur current conduction of said first transistor controls the . more slowly. If it occurred slowly enough, transistor T1 operation of the sending leg, means connecting said col would be slow in becoming conducting and transistor T2 lector element to a first source of relatively small nega would conduct momentarily before transistor T1 became conducting, and, during a time when a space was being 50 tive voltage through a diode and to a second source of larger negative voltage through a second impedance, and transmitted on the send side, a mark-to-space transition a third impedance connected from a common connection on the receive side would cause a marking hit on the between said small negative voltage source and said diode send side. The circuit of the present invention will oper to ground, said diode being so poled as to protect the ate at full duplex with a capacity of over .5 MF on the receive hub, which is considerably more capacity than 55 transistor from excessive collector voltages. . 3. The repeater unit as defined in claim 2 further hav would exist in practice on full duplex operation. ing a fourth impedance connected between said emitter On half duplex operation, the network to the base of element and ground to prevent excessive voltage on the Tl causes no load on the receive hub for the MM condi emitter element when the send relayv windings are re tion, and only causes a load when the voltage on the moved from said repeater.’ ' on the receive side will make transistor T1 conduct before transistor T2 can conduct and therefore transistor T2 can hub reaches -22 volts or more. This voltage is consider 60 ably beyond the changeover voltage of +15 at which the send hub is to go from mark to space. Therefore,` the operation of the send relay will have occurred before the network produces any load on the hub and ktherefore the network will cause no bias to signals even when l5 65 to 20 coupling units are connected to the same hub. Resistors Ri and R2 comprise the circuitry for the hit locator of a No. 2 service board. These resistors are the same as are used in the prior l44A1 unit and the 4. The repeater unit as defined in claim 3 further hav ing in said ñrst circuit means an impedance having a resistance of at least 5 megohoms connected to a nega tive voltage source of 130 volts to match the load pre sented to the send hub and to create added base-emitter current in said transistor so that if said transistor should become disconnected from said send hub, a space condi tion will -be sent to the distant oflice connected to said send leg thereby warning it has been cut-off from said sending hub. Y theory of operation is the same. 70 5. In a hub telegraph repeater unit adapted to be con The invention may be embodied in other specific forms nected to a receiving hub and a sending hub, said unit Without departing from the spirit or essential character having a control circuit interconnecting receiving and istics thereof. The present embodiment is therefore to sending legs for a single circuit for locking and unlock ing said sending legs in response to signaling conditions strictive, the scope of the invention being indicated by the 75 impressed on said receiving leg comprising: a ñrst tran be considered in all respects as illustrative and not re 3,033,929 siStOr; `a _first circuit means including a large impedance g . ' . v7. The repeater nnit as defined in claim 6 wherein »said connecting a .control element `of said fñrst Y'transistor to ' second `circuit means is connected to the receiving leg at saidrsending hub; means for connecting another element a point between thereeeivev relay and the receive hub. A 8. The repeater unit asïdeiined in clairn 5 further hav ing a third transistor having collector, base and emitter of said tirst transistor to said sending leg whereby the current Vconduction of said iìrst transistor controls the operation of the sending leg; a second transistor having emitter, >collector' and base elements with the coliector element connected to control current conduction through said ñrst transistor through a circuit having low im elements with its collector element> connected to one ter minal of said capacitor, its emitter element connected to a potential positive relative to they potential of the emitter element of said second transistor, and its base element pedance _whereby the current conduction through said 10 connected to said receive` hub whereby a double space on said receiveV hub causes said third transistor to conduct lsecond transistor is eiîective to override the signal on and thereby change the charge on said capacitor to pre the send hub in the ycourse of controlling current con vent said second transistor from being in a conductive duction in said first transistor;and a second circuit means including a rectifier, resistance and capacitorconnected to said second transistor for controlling the current con duction through said second transistorgthe charge on said >condenserchanging relatively quickly when a space sig condition. ` nal is present on said receivingieg to effect a change in the conduction condition of said second transistor, and 'changing much more slowly when a'rnark signal follows 20 the >space signal to provide a delay equal to approximately one pulse length of the telegraph code beingV transmitted before eiîecting a further change in the current conduc tion condition of said second transistor. 6. The repeater unit as deiìned in claim 5 wherein one 25 terminal von said capacitor is connected Vto the base ele ment of said second transistor through a paral‘rel circuit ~ ., Y 9.- The repeater unit as defined in claim 8 wherein the 15 _ connection between thebase element on said third tran sistor and said receive hub comprises a voltage divider and diode to increase the speed of response of said tran sistors> to enable full duplex operation. ~ y» References Cited in the tile of this patent UNITED STATES PATENTS 2,558,197Y Rea __________ __` ____ __ June 26, 1951 2,607,852 2,612,560 v2,636,942 Rea ________________ __ Aug. 19, 1952 Rea ________________ __ Sept. 30, 1952 Davey ______________ __ Apr. 28, 1953 comprising a resistance and a diode, the diode being OTHER REFERENCES ' ,poled soìthat leakage current that flows from the col Electronic and Radio Engineering, by F. E. Terman; 30 lector to base elements at high temperatures causes in McGraw-Hill Book Co., fourth edition, copyright 1955, suiiicient voltage drop across said resistance to change pages 632, 633, 777-781, 795.y ' the conduction condition ~of said second transistor.