US2833865A - Multistation remotely-controlled phonograph systems - Google Patents

Description

May 5, 1958 M, J, K UT|K 2,833,865

' uumsmuon amomY-comaouzzo PHONOGRAPH SYSTEMS Filed July 10,1956 2 Sheets-Sheet 1 i ii .1

INVENTOR 74 Marffnilfixtik May 6, 1958 M. J. KUTIK 2,833,865

' mum-non REUOTELY-CONTROLLED PHONOGRAPH s smus v Filed July 10, 1956 2 Sheets-Sheet 2 INVENTOR Martin J. Kucik United States. Patent MULTISTATION REMGTELY-CONTRGLLED PHONQGRAPH SYSTEMS Martin J. Kutik, New York, N. Y., assignor, by mesne assignments, to McGraw-Edison Company, Elgin, Ill., a corporation of Delaware Application July 10, 1956, Serial No. 596,867

19 Claims. (Cl. 179-1001) This invention relates to dictation-recording systems wherein any one of a plurality of remote dictators stations are connectable selectively to any one of a plurality of dictating machines, and more particularly the invention relates to improvements in such systems which will automatically select an available machine as soon as a dictator activates his station "and which will provide privacy against intrusion or interference from other stations to each dictator using the system.

Objects of the invention are to provide a simplified circuit arrangement and apparatus for accomplishing the aforestated privacy and automatic selecting functions in multistation dictation-recording systems.

Another object is to provide such improved systems wherein privacyand/or automatic selection are accomplished without increasing the number of lead wires between the machines and stations.

Another object is to provide such improved systems which do not require interposition of any impedance elements in the communication circuits between the machines and stations.

A further object is to provide a stepping switch at each dictators station for selecting an avaliable machine when a dictator closes his station switch, which is controlled according to the character of the voltagei. e., for example, whether an A. C. or 'D. C. voltage or a D. C. voltage of one polarity or another-which is supplied to the dictators station from the respective machine.

A still further object is to connect the dictators receiver to the line corresponding to the setting of the stepping switch to provide a sound signal at thedictators station to apprise him as to whenever his station is connected to a machine already in use.

Other objects and features of my invention will be apparent from the following description and the appended claims.

In the description of my invention reference is had to the accompanying drawings of which:

Figure l is a schematic circuit diagram of a dictationrecording system according to one embodiment of my invention; and

Figure 2 is a similar schematic circuit diagram showing a second embodiment.

The basic recording system in which my invention is herein shown is of the type disclosed in the pending Somers et al. application Serial No; 247,244, filed September 19, 1951 (now Patent No. 2,757,238, dated July 31, 1956), and to which reference may be had for details. For simplification of description, only those portions are described which are necessary to illustrate the invention and those portions are largely diagrammatically shown.

With reference to Figure 1, the dictating machines are provided at so-called attendants stations indicated by dash- dot enclosures 11c and 11d. The equipment is the same at the respective attendants stations and likewise itis the same'at the respective dictators stations, and in ice the description like parts at difierent stations are given the same reference characters.

At each attendants station there is a dictating machine 12, fractionally indicated, which comprises a record support, for example a turntable 13.carrying a disk record 14 and journaled in a bearing 15; The turntable is driven by a driving wheel 16 in frictional engagement with the periphery thereof and coupled by a clutch 17 to a motor 18. I Engaging the disk record area recorder 19 and a reproducer 20. These translating devices arecarried by a suitable carriage (not shown) for movement across the disk record, with the reproducer at a trailing distance behind the recorder, as the turntable is driven. During recording, audiosignals are fed to the record from a communication circuit 21 through an audio'transformer 22, record-reproduce switch 23, circuit 24,..and amplifier 25, and during reproducing audio'signalsare fed from the reproducer 20 through circuit 26, amplifier 27, the record-reproduce switch 23 and the audio trans:

former 22 to the communicationcircuit 21, it being 'understood that in this instance the record-reproduce switch is in a position making with its lower contacts. Direct current -is supplied to the communication circuit 21, as is hereinafter explained, through two control relays '28 and 29, but the audio current in the communication Cir cuit 21 is shunted past these .-rel'ays through a condenser St). the level of direct current in the communication circuit,

the relay 28 being operable at a lower current. level and i the relay 29 at an appreciably higher current level. As is later described, operation of the relay 28'is adapted to start the motor 18, and operation of the relay 29 is adapted to engage the clutch 17 through a-meclianical coupling represented by the'dash-dot line 31. Energization of the communication circuit 21 to operate the relay 28 and start the'motor18 while the amplifiers 25 and 27 are in operating condition is herein considered as an activation of the dictating machine. a I

At each attendants station there is also a signal transformer 32 connected to an A. C. source of power through the line 33 and plug 34. The secondary of thistransformer is connected normally to a signal circuit 35 through a single-pole double-throw switch 360i a relay 7 Each dictators station is connectable' to each com- 'munication circuit 21 of the several dictating machines through a branch circuit designated by the numeral'4 0 with suffix letters of the respective stations, andlikewise each dictators station is connectable to each signal circuit 35 of the several machines through a branch circuit designated by the numeral 41 with the SllffiX letters of the respective stations. At the dictators station the respective branch circuits connect to respective-sets of contacts of a four-pole stepping relay 42, the connections being such that the branch communication circuits connect to contacts associated with poles 43 and 44 and the branch signal circuits connect to contacts associated with the poles 45 and 46. Poles 43 and 44 are connected by a circuit 47 to the lower contacts of switches 49 and 5 0 of a station relay 51. The poles of these switches which make normally with the upper contacts-are connected to a circuit 52 serially including a normally-open switch 53-which constitutes one section of a multiple -on oif Patented. May 6, 1958 The relays are controlled selectively according tov herein necessary to describe.

3 station switch 54. Beyond the station switch there is connected to the circuit 52 the transducer elements of a telephone-type handpiece 55 including a receiver 56 and a carbon button microphone 57. When the handpiece is on its support or cradle it rests on an extension of the pole 53, dottedly shown, to hold the station switch open against the force of a spring connected thereto, but when the handpiece is removed from its support the station switch is closed by this spring. The receiver is connected across the circuit 52 through a blocking condenser 58 and resistor 59, the microphone is connectable across this circuit through a normally-open switch 60 which constitutes a record start-stop switch as later explained, and a resistor '61 is connected permanently across this circuit to form a direct-current connection across the communication circuit whenever the station relay 51 is operated and the on-ofi station switch 54 is in on position.

Leading from the poles 4S and 46 associated with the signal circuits is a circuit 62 at each dictators station one side of which is connected through a rectifier 63 and condenser 64 to the upper contact of the switch 49 in the branch communication circuit and the other side of which is connected through a lead wire 65 to the upper contact of the switch 50 in the branch communication circuit. Accordingly, upon closing the station switch 54 the dietators receiver is connected through the circuit 52, rectifier 63, condenser 64 and line 65 across the branch signal circuit. By this connection a hum signal is provided to the dictator as whenever his station is connected to an already-activated machine, as will appear.

Also, when a dicatator closed his station switch 54 a second section 66 thereof is closed to complete a signal circuit. 62 through the coil of the station relay 51 and through a switch 67 of this relay making with its upper contact. The switch 67 is operated to make with its lower contactwhen-the relay 51 is energized, and constitutes a holding switch to maintain the relay 51 operated after connection is made to an available machine, as will appear.

In order to understand the operations which occur when a dictator picks up his handpiece from its support, an

understanding must be had of the type of power-supply system provided at the attendants stations. All power for each attendants station is obtained, for example,'

through the plug 34 which is to connect to an A. C. power line not shown. Connected across the circuit 33 leading from this plug through a master switch 68 is the primary of a power transformer 6%. This transformer has a secondary winding 70 connected to a rectifier-filter pack 71 to supply a D. C. voltage at the terminals 72 connected to the communication circuit 21 through the control relays-28 and 29. The transformer 69 has also a second secondary winding 73 connected to a rectifier-filter pack 74 to supply a D. C. voltage at the terminals 75 for the-relay 37. The master switch is to be closed whenever a machine is on stand-by for use. A D. C. voltage is then provided to the communication circuit 21 and may then also be provided to the relay 37 through a circuit 76 including a normally-closed switch 77 of the control relay 28 and a safety switch 76a which is so controlled that it is closed only when the machine is in an operable condition-i. e., when a record is properly mounted on the turntable, the record- reproduce translating devices 19 and 25 are engaged with the record, etc. the control means for such switch being however not The relay 37 is-norrnally held in operated position with its switch 36 making with its upper contact to cause a D. C. voltage to be normally supplied to the signal circuit 35 through the rectifier 33. A second switch 78 of the relay 37 is connected in a circuit 79 of the motor Zi$ leading to the power source 34 through the master switch 68. However, the switch 78 is normally held open by the relay 37 so that the motor does not run until the machine is activated by a closing of its communication circuit 21..

When a dictator closes his station switch 54 while his station is connected by the respective stepping relay 42 to a dictating machine in an unused or available condition, the direct current in the signal circuit from that machine is prevened by the rectifier 63 from flowing into the audio circuit 52 because this rectifier is poled oppositely to the polarity of the D. C. source in the signal circuit. However, the closing of the second section 66 of the station switch completes the signal circuit through the station relay 51 to cause this relay to operate, this being a relay operable only by direct current to prevent its operation whenever A. C. voltage is supplied to the signal circuit. Operation of the relay 51 causes the switches 49 and St) to make with their lower contacts, the effect of which is to connect the audio circuit 52 of the dictators station to the communication circuit 21 of the dictating machine. For instance, as shown in the drawing, if the dictator at station 11d should pick up his hand-piece, connection would be made to the dictating machine of station 10b through the branch communication circuit 40bd and the branch signal circuit albd. As connection to the communication circuit is made, a circuit is completed immediately through the resistor 61 to cause direct current to flow in the communication circuit 2i to operate the relay 28. Operation of this relay opens the circuit 77 to cause the relay 37 to drop out. As the relay 37 drops out the switch 78 is closed to start the motor 18 and the switch 36 is made with its lower contact to shift the power supply in the signal circuit 35 from D. C. to A. C. The station relay 51 will however be maintained in operated position because as this relay was operated its holding switch 67 broke with its upper contact and made with its lower contact to interpose a rectifier 80 in series with the relay through the line 81 and to connect a filter-condenser 82 across the relay. if the dictator next closes his start-stop switch ml, the resulting connection of his carbon button microphone 57 across the audio line will increase the direct current in the communication circuit to cause the control relay 29 to operate and engagethe clutch. The machine will then be running for the normal recordation of dictation.

On the other hand, if the dictator closes his reproduce start-stop switch 33 at his station, connection is completed through the switch section 66 of the station switch between one side of his branch communication circuit and one side of his branch signal circuit to connect a recordreproduce relay 84 across the D. C. source at the terminal 72. As the relay is operated its switch 2.3aforementioned is moved to reproduce position to connect the communication circuit to the reproducer 2t and the clutch 17 is engaged by an operative connection designated by the dash-dot line 85 to start the machine. Reproduction of the recorded matter on the record Will therefore occur and be heard in the dictators receiver, the reproduction starting from a point backspaced from the recorder because of the reproducer being at a trailing distance behind the recorder as before stated.

From the foregoing description it is apparent that the effect of a dictator picking up his handpiece when his stepping relay is already in a position corresponding to an available machine is to make an operative connection to that machine with the resultant starting of the motor and with a shifting of the signal circuit of the machine from D. C. to A. C. This shifting of the signal circuit to A. C. will prevent any other dictators station from making operative connection to the machine already in use. For instance, if a dictator at another station closes his station switch while his stepping relay is in a position corresponding to the same machine, the A. C. voltage supplied from the signal circuit of that machine will not operate his station relay 51 because of this relay being operable only by direct current, with the result that he is unable to make operative connection between his audio circuit and the communication circuit of that machine. Instead, the A. C. voltage supplied to his station from the signal circuit of that machine is fed through the rectifier 63 and condenser 64 to provide a warning signal in his receiver to apprise him that his stepping relay is in a position corresponding to an unavailable machine. It

is therefore impossible for another dictator to intrude,

interfere or listen in on a station already having made operative connection to an available machine. This privacy is achieved as with respect to any single machine whenever the stepping switches of two or more dictators stations are in positions corresponding to the same machine. The stepping switches are therefore not necessary to achieve privacy but are provided to achieve automatic selection of an available machine whenever a dictator closes his station switch, as is herein next described.

If a dictator closes his station switch when his station is connected through his stepping relay to a dictating machine already-in use, an A. C. voltage is supplied from the signal circuit of that machine through the switch 67 making with its upper contact, line 81, rectifier 86, coil sults in the dictators station being connected to another machine already in use, an A. C. voltage is againsupplied through the switch 67 still making with its upper contact, line 81 and rectifier 86 to activate the stepping relay 42 again whereby the switches 43-46 are advanced by another step. This stepping action will take place automatically until connection is made to an unused or available machine. As such connection is made, the voltage supply in the signal circuit to the dictators station is shifted from A. C. to D. C., the D. C. voltage supply being however of a polarity opposite to the polarity of the rectifier 86. The current to the stepping relay 42 is therefore cut off so that this relay now remains at standstill. However, the D. C. voltage in the signal circuit will operate the station relay 51 to operate the switch 67 to its lower contact and to connect the receiver and resistor 61 across the communication circuit. Direct current will therefore flow in the' communication circuit from the D. C. source at the terminal 72 to operate the control relay '28. Operation of this relay opens the switch 77 to drop out the relay 37. As the relay 37 drops out the switch 78 is closed to start the motor, and the switch 36 is closed with its lower contact to shift the power supply in the signal circuit from D. C. to A. C. As aforestated, this A. C. voltage in the signal circuit is effective to maintain the station relay 51 in operated position because of the rectifying action of the rectifier 80 now in series with that relay. However,

since the switch 67 is now broken with its upper contact, the A. C. voltage in the signal circuit cannot operate the stepping relay 42 because the only circuit connection now made from the A. C. voltage source to this relay is through the rectifiers 80 and 86 and these rectifiers are poled in opposite directions to each other to block completely the flow of any current to the relay.

In the foregoing embodiment the respective stepping switches and station relays are controlled according to whether alternating or direct current is supplied to the dictators stations through the signal circuits 35 from the respective dictating machines. My invention contemplates that the stepping switches may be controlled by any suitable change in the character of the control voltage supplied from the respective machines, and as a further illustrative example I show in my second embodiment in Figure 2 an arrangement wherein the stepping switches and station relays are controlled by D. C. voltages according to whether the voltages are of one polarity or another. In other respects this I secondembodirnent is similar to my first embodiment. In describingthesecond embodiment, like parts are given the same reference characters, revised parts are given reference characters increased by 100 over those of the corresponding parts of my first embodiment, and new parts are given new reference characters. I

The attendants stations in Figure 2, referred to as 110:: and 110b, and the dictators"stations referred to as 111a and 111d are interconnectable by the same circuits and selector switches as in my first embodiment. At each attendants station a relay 137, corresponding to the previous relay 37, has the normally-closed switch 78, a single-pole double-throw switch 36, and an additional single-pole double-throw switch 88. The relay 137 is connected to the D. C. terminals 75 through theswitch 77, the same as before. The switch 78 is connectedin the motor'circuit toperform the samefunctionas. before. The switches 36 and 88 have their adjacent contacts joined together and connected by a lead 89 to one side of the secondary winding of the signal transformer 32 and have their other contacts joined together and connected by a lead 90 to the junction between the rectifier 38 and the filter-condenser 39in the circuit across the secondary winding of this transformer. When the relay 137 is energized-which it is whenever the machine is in an available or stand-by condition-the polarity of the D. C. voltage in the signal circuit 35 is as indicated at the point where the leads ofthe signal circuit leave the attendants station. However, when the relay 137 drops out,-the polarity of this control v'oltage in the signal circuit is reversed.

If a dictator closes his station switch 54 by picking up his handpiece from its support while the respective stepping switch is in a position corresponding to a machine in a standby condition, the D. C. voltage in the signal circuit is in the first instance prevented from finding a completed circuit through the switches 49 and 50, which are then making with their upper contacts, because of the blocking condenser 91. Also, this D. C. voltage will not find a completed circuit through the holding switch 67 making with its upper contact, the stepping relay 42, switch 87, rectifier 92, lead 93 and section 66 of the station switch 54, because the rectifier 92 is polarized in the direction opposite to that of the control voltage supplied in this circuit. However, this D. C. voltage will find a completed circuit through section 66 of the station switch 54, lead 93, rectifier 94, relay 51 and rectifier 95 to cause the relay 51 to be operated. Operation of the relay 51 completes the communication circuit 21. For instance, with respect to stations band 111c as shown in Figure 2, this completion of the communication circuit will be through the branch 40b0, poles 43 and 44 of the stepping relay 42, switches 49 and 50 making with their lower contacts, and the circuit 52. Also, as the relay 51 is operated, its holding switch 67 is shifted to its lower contact but with no immediate result. The completion of the communication circuit causes the relay 28 at station 11Gb to be operated to cause the relay 137 to drop out. Drop-out of this relay causes the motor circuit to be closed to activate the machine and it reverses the polarity of the D. C. voltage inthe signal circuit 35. This D. C. voltage of reversed polarity now continues to find a completed circuit through the station relay 51 via the holding switch 67 making with its lower contact, rectifier 96, relay 51, lead 97, switch 87, rectifier 92, lead 93 and section 66 of the station switch 54. Consequently, the station relay 51 is maintained in 01':- erated position to maintain the connection of the communication circuit of the station with the audio circuit of the machine.

When the operative connection ismade to themac'hine at station 1101: resulting in activation of the machine, the dictator can record or reproduce dictation in the same way as has been described in connection with my firstenianother stations of a second series.

bodiment. For. instance, to record he will press the switch 60 on his handpiece, the effect of which is to operate the relay 29 to engage the clutch. To reproduce, he will press the switch 83, the effect of which is to operate the relay 84 through the same circuit as before, the operation of this relay serving both to shift the record-reproduce switch 23 to reproduce position and to engage the clutch.

Once the machine at the station lltib is activated the polarity of the voltage supply in the signal circuit is such as to prevent any other dictators station making operative connection to that machine. For instance, it the dictator at station 111d next picks up his handpiece, the current supply is prevented by the rectifier 95 from activating the station relay 51. However, the current can flow through the stepping relay 42, through switch 67 making jwith'its-upper contact, relay 42, switch 87, rectifier 92, 'lead 93, and section 66 of the station switch 5 3. As a result, the stepping relay 42 is energized to advance the switch poles 43-46 by the one step in the manner hereinbefore described. If, as a result of this step advance of I the stepping switch, a connection is made to a machine in an already activated condition, the control voltage from that machine will have such polarity as to cause the stepping relay to be advanced by another step. This will continue until connection is made to a machine in a stand-by condition. When that occurs, the polarity or" the control voltage will be such as to cause the station relay 51 to operate. Such operation of the station relay will complete the connection of the communication circuit of the station 1110! with the audio circuit of the machine and cause the relay 28 of that machine to be operated to place the machine in an activated condition. The dictator at vstation 111d can then record and reproduce from that machine in the usual way.

From the foregoing description it wil be apparent that I have provided very simple apparatus which is operative whenever a dictator picks up his handpiece to cause his station to become connected to one or another of the several dictating machines in the system, provided one or another of the machines is in a standby condition. thermore, this apparatus is arranged to provide complete Furprivacy to each dictator using the system.

It is to be understood, however, that although I have described my invention in connection with a dictationrecording system it is not necessarily limited to this application, but is useful wherever it is desirable to automatically interconnect stations of one series with one or Moreover, it will be apparent that individual features of my invention may be employed individually and in subcombinations not comprising the over-all system herein described. The scope of my invention I endeavor to express according to the following claims.

I claim:

1. In a remotely-controlled selective phonographic system comprising a plurality of dictating machines each including a drive motor and a plurality of dictators stations:

the combination of a stand-by relay at each machine; a

master switch at each machine having on and ofi positions; communication and control circuits for connecting the stations selectively to said machines; means responsive to shifting the master switch at a machine to on position for causing the stand-by relay to shift from one position to another; and a power circuit for each motor controlled by therespective master switch and a switch of the respective stand-by relay, said latter switch being closed to permit said motor to run only when the stand-by relay is in said other position.

2. In a remotely-controlled selective phonographic system comprising a plurality of dictating machines, and a plurality of dictators stations each having an on-off station switch and a transducer means: the combination of a stand-by relay at each machine; a master switch at each machine; communication and control circuits controlled -.by said station switches for connecting the stations selecmeans at each machine for supplying direct current to the respective control circuit when the stand-by relay is in said other position and alternating current to the control circuit when the relay is in said one position; and means to cause the stand-by relay of a machine to shift to its said one position upon making an operative connection of a dictators station to the machine responsive to moving the respective station switch to on position.

3. The combination set forth in claim 2 including a station relay at each dictators station having switch contacts in the respective communication circuit which are open when the relay is not operated, said relay being operable only by direct current; and said on-olf station switch at each dictators station serially including switch contacts in the respective control circuit for completing said circuit through the respective station relay to cause the relay to operate when thecontrol circuit is supplied with direct current.

4. The combination set forth in claim 3 including a control relay at each machine connected in the respective communication circuit, means for supplying current to the communication circuit to operate said control relay when a dictators station is operatively connected to the machine by the closing of the respective on-ofi station switch and operation of the respective station relay; switch means op erable by said control relay for causing the respective stand by relay to be shifted to its said one position to restore alternating current to the control circuit when an operative connection is made between the station and the machine; and a holding circuit including a rectifier and switch contacts of the station relay for maintaining the station relay operated by the alternating current supplied in said control circuit after the stand-by relay is returned to said one position.

5. The combination set forth in claim 4 including a stepping relay at each dictators station for connecting the station to said machines in succession as the relay is stepped from one position to the next; and means including a rectifier for connecting the stepping relay in the respective control circuit, said rectifier being poled in opposition to the polarity of the D. C. voltage which is supplied to said control circuit from said machines.

6. In a remotely-controlled phonographic system comprising a plurality of activatable dictating machines and a plurality of dictators stations: thecombination of a communication circuit and a control circuit for selectively connecting each dictators station to any of said machines; means for activating an available machine when connection is made thereto; means for providing direct current to said control circuit when connection is made to a machine in a stand-by condition and for providing alternating current to said control circuit when connection is made to a machine which is an activated condition; a stepping relay in each control circuit operable into successive positions to connect the station to successive machines; a rectifier in series with each stepping relay poled oppositely to the D; C. voltage in the control circuit when the machine is in a stand-by condition whereby to prevent operation of the stepping relay, said rectifier passing pulses of current to operate said stepping relay when alternating current is provided; and means responsive to making operative connection to an available machine for rendering inoperative the respective stepping relay.

7. The combination set forth in claim 6 including an on-off station switch at each dictators station serially including a switch element in said control circuit which is open when the on-otf switch is in 05 position, and a circuit including said switch element for completing connection to said stepping relay when the station switch is in on position. p

8. The combination set forth in claim 7 including a station relay at each dictators station Operable only'by direct current and having a switch element serially included in the respective communication circuit in normally-open position and rendered closed when the relay is operated whereby closure of said communication circuit is efiected only by connection to a machine in'a standby condition; and a holding circuit for said station relay including contacts controlled by the relay and a rectifier for supplying rectified current to maintain the station relay in operated position when alternating current is supplied to the control circuit responsive to the completion of an operative connection between the station and a machine.

9. In aremotely-controlled phonographic system comprising a plurality of activatable dictating machines and a plurality of dictators stations: the combination of a communication circuit and control circuit for selectively connecting each dictators station to said machines respectively; means for activating an available machine when an operative connection is made thereto; means for providing a voltage to said control circuit of one character when a machine is on stand-by and of another character when a machine is activated; a stepping relay in each control circuit operable into successive positions to connect the dictators station to successive machines; and means in each control circuit to enable the respective stepping relay to be operated only by voltage of said other character.

10. In a multistation remotely-controlled dictation recording system including a dictating machine having a recording apparatus, and a plurality of dictators stations each having a transducer and an on-otf station switch: the combination of a communication circuit and a control circuit leading from each machine and having branch circuits leading to said stations respectively; means at each machine for providing direct current to its control circuit when the machine is in a stand-by condition and alternating current when the machine is operatively connected to a dictators station, each station switch including a normally-open switch element in the respective control circuit rendered closed when the station switch is shifted to on posit-ion to complete the control circuit and start the flow of either direct or alternating current therein according to whether the machine is in a stand-by condition or in use; and a relay at each station having a coil and respective control circuit and normally-open switch contacts in the respective communication circuit, said relay being operable by the direct current in said control circuit when the machine is in standby condition to close the respective communication circuit with said machine and being inoperable by the alternating current in said control circuit when the machine is already operatively connected to a dictators station.

11. The combination set forth in claim 10 including a stepping relay at each dictators station for selectively connecting the station to said machines in sequence; means for connecting the stepping relay to the respective control circuit including a rectifier poled to prevent operation of the stepping relay by direct current supplied to the control circuit from the respective machines when the machines are in stand-by condition, said rectifier being adapted to pass pulses of current to the stepping relay to operate the same when connection is made to a machine in an unavailable condition; and means responsive to completion of an operative connection between a dictators station and an available machine in a stand-by condition for effectively disabling the respective stepping relay.

12. The combination set forth in claim 11 including a circuit at each dictators station controlled by the respective station relay for feeding alternating current to the transducer of the dictators station to provide a warning signal whenever connection is made by the respective stepping relay to an unavailable machine.

13. In an automatic selector system comprising first and second series of stations each having; dual circuits leading therefrom, each of saidfirst series of stations having circuit-closing switch means in its dual circuits and each of said second series of stations having a *D. C. power source connected toone of its circuits and a D. C. source normally connected to the other-of its circuitswith means to change the connection to an A. C. power source when the stated one circuit of the respective station is energized to activate the station: the combination of a stepping relay for each of said first stations having switches for connecting the dual circuits of a station to the dual circuits of said second stations respectively; a station relay at each of said first stations normally inactivated and having switches for connecting one of the dual circuits of the station to said one circuit of the second station corresponding to the setting of said stepping relay, said station relays being operable only by direct current; means responsive to closing said one of the dual circuits of a first station through said one circuit of a second station for feeding rectified power from the A. C. supply in the other circuit of said second station to the stepping relay to activate the same; means responsive to the steping relay reaching a position corresponding to an inactivated second station for blocking the flow of power from the D. C. source of said other circuit of said inactivated station to the stepping relay and for activating the respective station relay from said D. C. source; means responsive to activation of said station relay for activating saidsecond station with restoration of A; C. power to said other circuit of said second station; and means responsive to activation of said station relay for blockingthe flow of operating current to the stepping relay from the A. C. power source in said other circuit of said second station so long as said station relay is activated.

14. in an automatic selector system for independently interconnecting first and second series of stations, said second stations being characterizer as having a D. C. power source therein when in an inactivated condition and an A. C. power source therein when in an activated condition: the combination of a stepping relay for each of said first stations for connecting the station to said second stations respectively; switch means at each of the first stations closable to complete connection of the respective stepping relay to the power source of the second station corresponding to the setting of the stepping relay;

a rectifier in said connection to enable operation of the stepping relay from the A. C. power source, said rectifier being poled to block energization of the stepping relay from the D. C. power source; and means at each of said first stations responsive to connection of the station to an inactivated second station for introducing a second rectifier in said connection poled in opposition to said first rectifier for preventing operation of the stepping relay from the A. C. power source.

15. The combination set forth in claim 14 including a station relay at each of said first stations normally inactivated and activatable only by the power source of a second station when the power source is direct current: and means responsive to operation of the station relay for converting the power source of the second station from D. C. to A. C. and for activating the respective second station.

16. The combination set forth in claim 15 including a holding switch for each station relay operable by the relay for causing it normally to be maintained in operated position when the power source of the respective second station is alternating current.

17. In an automatic selector system: the combination of a series of activatable machines having circuits leading therefrom; means for providing voltage of one character in the circuits leading from the respective machines when the machines are in stand-by condition and voltage of another character when the machines are in activated condition; a series of operators stations each having a stepping relay for connecting the same to said activatable assases machines respectively; means for rendering said stepping relay inoperable byvoltage of said one character from a machine in a stand-by condition; an on-ofi station switch at each operators stationmovablc to on position to render the respective stepping relay operable by voltage of said other character from a machine in an already activated condition when connection is made thereto, whereby the stepping relay is stepped ahead to its next position, and for causing activation of a machine with conversion of said voltage thereof from said one to said other character when connection is made thereto while the machine is in a stand-by condition; and means operative as a machine is activated following connection of an operators station thereto for causing the stepping relay of said station to be rendered inoperable by voltage of said other character from said machine.

18. The combination set forth in claim 17 wherein said voltage of said one character is D. C. voltage of one polarity and said voltage of said other character is D. C. voltage of the opposite polarity.

1.9. In a remotely-controlled phonograph system comprising a plurality of dictating machines and a plurality of dictators stations: the combination of interstation communication and control circuits including selector switches for making a dual circuit connection between each station and said machines respectively, each of said machines having an audio circuit connected to said interstation communication circuits and a source of control voltage connected to said interstation control circuits; means at each machine for activating the machine for start-stop operation, each of said machines being adapted to cause said control voltage to be of one character when the machine is in a stand-by condition and to be of another character when the machine is in an activated condition; an on-ofi station switch at each dictators station movable to on" position to complete the control circuit of the one machine corresponding to the setting of the respective selector switch; means at each station in the respective control circuit responsive only to control voltage of said one character for completing the communication circuit of the station with the audio circuit of said one machine when said one machine is in a stand-by condition and for activating said one machine; means operated incidental to the completing of the communication circuit of the station with the audio circuit of said one machine for rendering the last aforcstated means responsive to control voltage of said other character whereby to maintain said communication circuit in a completed state and said one machine in activated condition; and means in the control circuit of each dictators station adapted to cause the respective stepping switch to be operated by one step when the control circuit receives a voltage of said other character from a machine in an already activated condition.

No references cited.

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