US1623480A - Transmission system - Google Patents

Description

' A ril 1927.

' 5 I J. 'J. KUHN TRANSMISSION SYSTEM Filed Feb. 28. 1925 2. Sheets-Sheet 2 Patented Apr. 5, 1927.

UNITED STATES 1,623,480 PATENT OFFICE.

JOHN J. KUHN, OF ELIZABETH, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

I TRANSMISSION SYSTEM.

Application filed February 28, 1925. Serial No. 12,249.

This invention relates to systems for the distribution of musical and other programs ovcr wires, and more particularly to announcing circuits associated with such systems.

The object of the invention is to enable a supervising operator or announcer .to make announcements simultaneously to all subscribers connected to the system in the event that it is desired to call attention to special program features or to spread an alarm signal in an emergency.

The invention finds a particular application in what have been called apartment house radio systems. In these systems,

which are described in the applicants co-' pending application, Serial No. 648,938 filed July 2, 1923, broadcast radio programs are received at a central station, for example, in a hotel or apartment building, and after detection and amplification are distributed by wire to subscribers reproducing instruments in the various apartments. Several programs may be distributedsimultaneously by different wire circuits any one of which may be selected by the subscriber.

By means of the present invention the operator supervising the radio reception is enabled to connect all subscribers instruments simultaneously v to an announcing inicrophone regardless of any connection previously made by the subscriber.

In the detailed description which follows the nature and operation of the invention will be described in connection with a program distribution system of this type. It is to be understood, however, that the invention is not limited to such systems. Other applications of the invention will be evident from the description.

Figs. 1 and 2 of the accompanying drawings illustrate'in schematic form systems embodying alternative forms of the invention.

In Fig. 1, PT,, PT and PT are three program trunks entering the central station and each carrying waves corresponding to separate programs. In the system illustratedselected radio broadcast programs are received by radio upon antennae such as 1 and are delivered to the trunks through detecting and amplifying systems such as 2. These translating systems may be of any well known type, and since they form no part'of the present invention they are illustrated only conventionally. Instead of using a radio link the program trunks may, if desired, be run directly to the studios at which the programs originate.

The program trunks are connected to main bus-bars B and B, and B from which circuits branch to the subscribers stations, three of the latter being indicated at S S and S The equipments at the subscriber station are the same. One such equipment 5, as viewed in the drawing, the terminals of'the loud speaker are short circuited and the subscribers. line is closed through resistance 6 which is sufficiently large to prevent a short circuit of the system. In the other positions of the switch resistances 6 and 7 cooperate to vary the current intensity in the receiver so that, as the switch contact is moved step-by-step to the right, the received volume is progressively increased.

The announcers circuit comprises a microphone 8 located at the central station, an energizing battery 9, and a repeating coil 31 through which the microphone is connected to trunk line 10. Branch lines from trunk 10 extend to each subscriber station and terminate in front contacts 11 and 12' of relays such as 13. The relays 13 at each station are connected in multiple to a common line 14 in which is included battery15- and key 16 the latter being under the control of the operator or announcer. The subscribers telephone is connected to armatures 17 and 18 of relay 13 and normally through back contacts 19 and 20 to the volume control switch in the program line.

l/Vith this arrangement the operator or announcer is enabled by closing key 16, and thereby operating relay 13, to transfer the connections of all of the subscribers telephones to the announcing trunk line 10. Further, since the announcing line is connected bythe operation of the relays 13 directly to the telephone instrument terminals, closure of the switch 16 connects the operators announcing circuit with each station battery receiver regardless of the condition of the An. additional contact 22 on this switch serves to close acircuit through battery 15 which is applied. to theline when the line is connected to .the announcers circuit. Speech currents are-prevented entering the circuit, which is bridged across the lineby choke coils 123 and the battery currentis prevented entering the repeating coil 11 of the announcers circuit by line condensers 24.

One of the-subscribers stations is shown in detailed schematic at S,'. The circuit arrangements are similar to those of the sta tion S of Fig. 1, but the operating winding of the relaylB is bridged acrossthe incoming line connected to program trunk PT instead of being served by a separate line. In addition line condensers 25 are provided to confine the direct current foroperating the relay to the relay circuit.

In the normal operation of the system the switch 21 is thrown to its left hand position whereby the-incoming program is delivered to the trunk-PT and thence through the connected branch lines to the subscribers" sets. The relay 13 is normally deener-- gized and the telephone receiver 3 is connected through the back contacts of inner armatures .17 and 18 to the terminals of volume control switch 5 and thence through selecting switch 4 to such one of the incoming'lines as may be selected by the subscriber.

The line condensers 24 and 25 add their impedances to the line and hence, to maintain a high quality of transmission, they should be of large capacity. For analogous reasons the im edances of rela 13 and choke coils 23 shoulc be large.

-\Vl1en the central station operator, desiring to make an announcement, throws swltch --2ltoits right hand position battery is applied through trunk PT and, through the connected branch lines. to the control relays '13. "At each subscribers station the energizing of relay 13 causes the telephone receiver 4 to be connected through the frontcontacts o'f armatures 17'and 18 to the terminals ofv the'incommg line connected to trunk PT which in this arrangement now corresponds to the announcers circuit 10 of Fig. 1. At

the same time the connections between switch 4 and volume control switch 5 are broken at the back contacts of additional armaturcs 29 and 30. This prevents the volume control switch acting as a shunt on the telephone receiver as it might'in the event that the subscribers were already connected to the incoming branch line from program trunk PT,, and so ensures that an announcement or alarm signal will he heard.

What I claimed is:

1. In a program distributing system, a. central station, an incoming program trunk terminating thereat, a plurality of subscribers stations each including a signal reproducing instrument, lines for connecting said reproducing instruments to said trunk, a signaling device at said central station, lines connecting said device to said subscribers stations, and means at said subscnbers stations, remotely controlled fromsaid central 1 station, for simultaneously connecting said signal reproducing instruments andsaid'signaling'device.

2. In a program distributing system, a central station, a plurality of subscribers stations, pro-gram trunks terminating at said central station, each of'said program trunks strument at each'of said subscribers s'ta-' being connected to said subscribers stations tions adapted to be connected byselective switching means to any one of said lines, a

signaling device at said central station, lines connecting said device to said subscrlbers stations, and relay switching means at said subscribers stations, remotely controlled from the central station, whereby said signal reproducing instruments may be. simultaneously connected to said signaling device.

3. A program distributing system, a central station from which a plurality rate lines radiate to subscribers stations, signal reproducing instruments at each subscribers station and meansfor selectively connecting said instruments to any one of of sepa- 1 said lines, an announcers microphone at said central station, means for lmpressmg speech signal'reproducinginstruments at said subscrlbers statlons adapted to be connected by p selectiveswitchmg means to any one of said lines, an announcers microphone at said central station, means for impressing speech currents therefrom upon one of said lines, means for impressing continuous currents upon said selected line, and a relay at each subscribers station connected to said selected line, adapted to be energized by said continuous current, to connect the subscribers signal reproducing instrument and said microphone.

5. A program distributing system comprising a central station, program trunks terminating thereat, a plurality of subscribers stations, separate lines connecting each of said trunks 'to said subscribers stat-ions, signalreproducing intruments at said subscribers stat-ions adapted to be connected by selective switching means to any one of said lines, an announcers microphone at said central station, switching means at said central station 'for connecting one of said lines to said microphone and for simultaneously impressing a battery voltage upon said line, and arelay at each subscribers station adaptedto be operated upon the application of said voltage to the selected line to connect the subscribers signal reproducing instruments and said microphone.

In witness whereof, I hereunto subscribe my name this 25thday of February A. D.,

JOHN J. KUHN.

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