US2129332A - Telephone system - Google Patents

Description

Patented Sept. 6, 1938 v UNITED STATES PATENT OFFICE TELEPHONE SYSTEM Domenico Mastini, Rome, Italy Application April 8 1935, Serial No. 15,342 i In Italy March 20, 1935 11 Claims. (Cl. 250-6) My invention relates to telephonic or teleremote radio station I and any subscriber 3 of graphic connection between two points in which a telephone network, whether of dial or other use is made, for a portion of the distance betype. tween said points, of any kind of conventional The diagram of Fig. 2 serves to explain the type of telephone network, for example, networks construction shown in Fig. 1. In Fig. 2 there 5 having local or central battery, or an automatic is the remote, the stationary or movable radio system, wireless transmitting means such as elecstation I, the interposed complex I, the teletromagnetic or light waves being used for the phone apparatus 9 connected with the local staremainder of.the distance between two points. tion, and the telephone central 5. The station 10 My arrangement requires no change at the cen- I consists of a transmitter I1 and a receiver I9, 10

tral telephone plant, the only change which is with the corresponding aerials. The complex I required being at the individual subscriber's staconsists similarly of a stationary wireless transtions where there is added what I call a committer 2I and a receiver 23, with the correspondplex, which is used instead of the ordinary in- .ing aerials.

dividual telephone instrument, there being a con- Two cases are now possible: 15 versation connection combined with said com- (1) The radio station I calls any subscribers plex. station 3.

In the accompanying drawing, by means of (2) Any subscribers station 3 calls the radio whichIillustrate my invention, station I.

Fig. 1 is a schematic view exemplifying the In case 1 the conversation circuit is established 20 general principles of my invention, and in the following manner: As long as a micro- Fig. 2 is a diagram of the circuits which I phone at the radio station I is hung up, the may employ. transmitter ll of station I is inoperative, and

The principle of my invention is first explained both microphone and the transmitter circuits 25 with reference to Fig. 1, wherein a remote radio are open. Upon the lifting off of the micro- 25 station I, either portable or stationary, is to be phone, however, both circuits are closed by the connected with a particular subscriber station hook 21 and the transmitter begins to send a 3 through a central station 5. The radio station carrier wave and, so long as there is no modu- I, through radiated energy, efiects the remote lation, continues sending this carrier wave which control of a complex 'I, which is associated with is received by the stationary receiver 23, is am- 30 a telephone sub-station. Under the actuation of plified in high frequency amplifier 29, and is this remote control, the complex I is connected passed on to a detector tube 3|. In this case with the central station 5,while the ordinary telethe detected high frequency oscillations prophone apparatus 9 at the sub-station is disconduce a direct current and this will give rise to nected from the network, and gives rise to a potential at the ends of a variable poten- 35 operations in the network circuit of the centiometer 33 in the cathode circuit of the detral station similar to those which would have tector. A portion of this potential is passed to been produced had the apparatus 9 called the a low frequency amplifier 35, while the total apparatus 3 directly. The radiant energy, modpotential drop acts on the grid circuit of a sub- 40 ulated at the remote radio station I, passes to sequent tube 31. This tube. 31 is directly cou- 40 the complex I, and the voice-modulated current pled with an amplifying stage (tube 39), the passes over the previously established wire confunction of which is to amplify both the moduversation circuit of the telephone network to lated current and the direct current. the subscriber station 3. A bridge system is provided in the plate cir- Conversely, an incoming call made from any cuit of the tube .39 across the points (apices) 4,5 subscribers station Will actuate a transmitter in of which there is connected an impulse relay 4| the complex 1 tuned to the receiver circuit of which is connected in series with a milliamthe remote radio station I, which transmitter, meter 43. By suitably adjusting a regulating rethrough the radiated energy, actuates a receiver sistance 45 in the bridge, the latter, in the abin the remote station I and upon response of the sence of a carrier wave. can be set to zero, or 50 latter, completes the conversation circuit I3. balanced.

My inventive concept is explained in greater On the other hand, ifa carrier wave is transdetail with reference to Fig. 2 of the drawing. mitted, a potential variation will take place, the This figure diagrammatically shows a combined bridge is no longer in balance, the milliammeter radio-telephone network connection between a indicates the passage of current, the relay II is 55 excited and closes the feed circuit of a relay 41. The relay 41, with the switches 49 and 5|, shifts the telephone line, consisting of the wires 53 and 55, to the non-local circuit, these wires 53 and 55 being then connected through two transformers 51 and 59 with the output circuit of the stationary receiver 23 and with the input circuit of the stationary transmitter 2|. The same relay 41, through a contact 6|, also actuates the station transmitter 2|. An armature 63 also closes the circuit to the central station 5 and opens a shunt circuit normally across the transformer 59.

Calling impulses coming in from station I may then be sent over the line to the central station.

The oscillator grid circuit of the transmitter I1 is connected to the movable element 65 and to the upper contact 61 of a dialing device 69; A:

lower contact 1| is also associated with the element 65 and the terminals of a grid biasing bat-. tery 13 are connected, respectively, to the contacts.

The grid biasing battery, therefore,,is intere mittently interposed in the grid circuit of the oscillator by actuation of the dialing device, the polarity of the battery and its potential being such that the grid receives a blocking negative voltage when the said battery is in circuit. When the element 65 is in the position of rest, as shown in the drawing, the oscillator may function normally.

The interruptions of the oscillating current, or of the carrier wave, corresponding to the desired subscribers number, operate, at the receiver 23, to cause the relay 4| to vibrate and thus impose upon the telephone lines 53-55 the number of pulses required for the calling of the desired subscriber 3.

When this is done and the subscribers station 3 is not busy, conversation can be begun, as the modulations coming from themovable transmitter are sent into the wire circuit by the stationary receiver 23 and the coupling transformer 51, while the modulations emitted by the wire circuit pass through the coupling transformer 59 to the stationary transmitter 2| and from there, by wireless, to the movable receiver I9.

In the second case (2), when the call goes out from any subscriber 3 of the telephone network a slow release relay 15is actuated thereby. This relay is of the thermic type and, after being energized, holds the armature attracted for thirty seconds or for any other suitable period of time. A contact 11 of this relay actuates the transmitter T and a contact!!! actuates a buzzer 8|, in the grid circuit of transmitter 2|. The transmitter 2|, therefore, will send oscillations, which are modulated by the inherent frequency of the buzzer and which are received by the movable receiver I9 and passed to the associated telephone apparatus 83. There they produce a call and, if it corresponds to the number of the sta-.

tion I and is answered, microphone 25 will be taken off. As a result, the movable transmitter |1 now sends a carrier wave which, after amplification and reception through the stationary receiver 23, actuates the relay 4| therein, which establishes the conversation circuit. Relay 4| actuates relay 41 which switches in the telephone line and at the same time closes the feed circuit of the stationary transmitter 2|, which was previously closed for a short time throughthe relay 15. After these operations the wireless conversation circuit is 'estabilshed.

When the telephone network is manual rather than of the dial type, the-plant issimplifiedflit' being suflicient to establish connection with the central exchange in the manner described previously, and, in a central having local batteries, to send out another calling current.

The circuit described herein only by way of example may be modified in different ways. For example, other rays, for example, light rays, may be employed instead of radio connections.

I claim as my invention:

1. In combination, a remote radio transmitter, a local telephone sub-station, a central station, wire lines normally interposed between said local sub-station and said central station, local radio receiving apparatus and means whereby radio signals received by said local receiving apparatus from said remote radio transmitter cause the disconnection of the local sub-station from the wire lines and the connection of the radio receiving apparatus thereto instead.

2. In combination, a remote radio transmitter, a local radio transmitter, a local radio receiver, a local telephone sub-station, acentral telephone station, Wire lines normally connecting said substation to said central station, and means responsive to an incoming radio signal, from said remote station, for causing the sub-station to be disconnected from said wire lines and for causing the connection to said lines of said local radio transmitter and said local radio receiver.

3. In combination, a remote radio transmitter, a local radio transmitter, a local radio receiver, a local telephone sub-station, a central telephone station, wire lines normally connecting said substation to said central station, and means whereby a signal from said remote transmitter, after demodulation by said local receiver, causes the disconnection of said wire lines from said substation, the connection of said local radio receiver and said local radio transmitter to said wire lines and the energization of said local transmitter.

4.. Incombination, a remote :radio transmitting and receiving station, a local radio transmitting and receiving station situated near a local telephone sub-station, a central station, wire lines normally interposed between said local substation and said central station, and means by which the local radio transmitting and receiving station, by the action of the energy transmitted from the remote radio transmitting and receiving station, is connected to the central station and the local telephone sub-station is disconnected.

I 5. In combination, a central telephone station,

a telephone sub-station, two wire lines normally connecting the sub-station and the central station, a local radio transmitter and receiver associated with the sub-station, a remote radio transmitter and means for disconnecting said sub-station from said wire lines and connecting said local transmitter and receiver thereto in lieu thereof, said means being responsive to radiant energy received from said distant radio transmitter.

6. In combination, a central telephone station, a sub-station, two wire lines extending from the central station to the sub-station, a local radio transmitter and receiver disposed in proximity to the sub-station, a remote radio transmitter and receiver, means whereby a carrier wave received by the local radio receiver causes disconnection of the sub-station from the lines and connection to said lines of the'local radio transmitter and receiver as well as energization of the local transmitter and means at the remote transmitter for producing calling impulseswhereby said remote radio transmitter and receiver may be placed in communication with a predetermined sub-station associated with said central station.

'7. In combination, a central telephone station a sub-station, a communication channel, constituted by at least two wires, extending from the central station to the sub-station, a local radio transmitter and receiver disposed in proximity to the sub-station, a remotely disposed radio transmitter and means associated with said local radio transmitter and receiver for operatively connecting both of them to said communication channel and for disconnecting the sub-station therefrom in response to the reception by said local receiver of a carrier wave from said remote transmitter, said means, upon cessation of said carrier wave, also functioning to disconnect said local transmitter and receiver from said communication channel and to reconnect the substation thereto.

8. In combination, a remote radio transmitting and receiving station, a local radio transmitting and receiving station situated near a local telephone sub-station, a central station, wire lines normally interposed between said local substation and the central station, means by which the local radio transmitting and receiving station, by the action of the energy transmitted from the remote radio transmitting and receiving station, is connected to the central station and the local telephone station disconnected, means for transmitting a calling signal, means responsive to said calling signal for producing momentary energization of the local transmitter, and a signal device at said local sub-station energized by said signal, said last-named means and said device being operative contemporaneously.

9. In combination, a remote radio transmitting and receiving station, a local radio transmitting and receiving station situated near a local telephone sub-station, a central station, wire lines normally interposed between said local substation and the central station, means by which the local radio transmitting and receiving station, by the action of the energy transmitted from the remote radio transmitting and receiving station is connected to the central station and the local telephone station disconnected, means for producing momentary energization of the local transmitter and for modulating the carrier wave of the local radio transmitter for sending to the remote radio receiver a calling signal, and a signal device at the local sub-station, both said device and said lastnamed means being activated by a calling signal coming from the central station.

10. In combination, a remote radio transmitting and receiving station, a local radio transmitting and receiving station situated near a local telephone sub-station, a central station, wire lines normally interposed between said local station and the central station, means by which the local radio transmitting and receiving station, by

the action of the energy transmitted from the remote radio transmitting and receiving station is connected to the central station and the local telephone station disconnected, means for producing momentary energization of the local transmitter and for modulating the carrier wave of the local radio transmitter for sending to the remote radio receiver a calling signal, a signal device at the local sub-station, both said device and said last-named means being activated by a calling signal coming from the central station, and means for disabling said means for producing momentary energization in response to said energy received from the remote radio station.

11. In combination, a remote radio transmitting and receiving station, a local radio transmitting and receiving station situated near a local telephone sub-station, a central station, wire lines normally interposed between said local station,

and the central station, means by which the local radio transmitting and receiving station, by the action of the energy transmitted from the remote radio transmitting and receiving station is connected to the central station and the local telephone station disconnected, means for producing momentary energization of the local transmitter and for modulating the carrier wave of the local radio transmitter for sending to the remote radio receiver a calling signal, a signal device at the local sub-station, both said device and said lastnamed means being activated by a calling signal coming from the central station, and means for disabling said means for producing momentary energization in response to said energy received from the remote radio station and means at the remote radio transmitter for producing carrier wave impulses which after demodulation by the local radio receiver are sent to the central station for selecting and calling the desired subscriberstation.

DOMENICO MASTINI.

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