Circuit connecting a voice-controlled device to a telephone station and line
This application is a continuation of application Ser. No. 06/753,841, filed July 11, 1985, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a circuit arrangement for connecting a voice-controlled additional facility associated with a telephone station to a telephone line, the voice-controlled additional facility containing a voice recognition unit and a selection control means. 
     A telephone subscriber station enabling voice-controlled dialling of the subscriber to be called through direct acoustical entry of words and/or numbers via the receiver microphone has already been described in Federal Republic of Germany patent application No. P 33 38 484 3. 
     However a disadvantage of the described arrangement is that engineering modifications must be performed in the telephone station in order to attach the voice-controlled additional facility. 
     SUMMARY OF THE INVENTION 
     It is the technical object of the present invention to create a circuit arrangement for connecting a voice-controlled additional facility associated with a telephone station to a telephone station. 
     A circuit arrangement according to the present invention of the type cited at the outset is characterized in that a switching unit of a connection means is looped into an a-conductor, a b-conductor and a ground wire of the telephone line, and is also connected with the voice recognition unit and, via an interrupt unit of the connection means, with the selection control means, thereby connecting the telephone station via the telephone line either to an exchange or to the voice-controlled additional facility, in that the connection means has a line status identification logic means, a dialling unit, a loop monitoring means and a grounding key monitoring means, which are looped into the telephone line and are also attached to the selection control means via a first interface of the voice-controlled additional facility, and in that a first switch, which connects the a-conductor and the b-conductor in the connection means, is connected with the selection control means via the first interface. 
     A particular advantage of the present invention is that any desired telephone station can be connected with the voice-controlled additional facility without engineering modification. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The sole FIGURE is a block diagram illustrating a voice-controlled additional facility which can be connected to a telephone station via a connection unit. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As can be seen from the only FIGURE, a voice-controlled additional facility 2 has a selection control unit 4, which is attached to a voice recognition unit 6 via an adapter unit 8 and is also attached to a first interface 10. 
     A switching unit 12 of a connection unit 14 is looped into an a-conductor a, a b-conductor b and a ground wire G of a telephone line 16, and is also connected with voice recognition unit 6, as well as with selection control unit 4, via an interrupt unit 18 of connection unit 14. 
     Connection unit 14 contains a line status identification logic unit 20, looped into a-conductor a and b-conductor b, a dialling unit 22, connected with a-conductor a and b-conductor b, a ground key 24, a grounding key monitoring unit 26, connected with ground wire G, and a loop monitoring unit 28, cooperating with a-conductor a and b-conductor b. Each of these four units is connected with selection control unit 4 of voice-controlled additional facility 2 via first interface 10. Moreover, a first switch 30 in connection unit 14, which connects a-conductor a and b-conductor b, is attached to selection control unit 4 via first interface 10. 
     If a receiver of an associated telephone station 32 is now taken off-hook, loop monitoring unit 28 signals the selection control unit 4, via first interface 10, that the loop of telephone line 16, which is connected with telephone station 32, has been closed. If, for example, line status identification logic unit 20 has identified an incoming call (no dial tone), selection control unit 4 is notified of this status via first interface 10. Connection unit 14 is then switched to the so-called &#34;transparent mode&#34; by selection control unit 4, i.e. it is not possible for connection unit 14 to influence the voice channel (a-conductor a, b-conductor b). 
     However, if an outgoing call is signaled to selection control unit 4 through detection of a dial tone by the line status identification logic unit 20, selection control unit 4 then initiates the following: 
     First of all, switch 30 is closed, thereby preventing the loop current from being interrupted. Telephone station 32 is then connected with the voice-controlled additional facility 2 by switching unit 12, via telephone line 16. To accomplish this, the voice channel (a-conductor a and b-conductor b) and ground wire G are first connected with voice recognition unit 6 via a first switching member 34, a second switching member 36 and a third switching member 38 of switching unit 12 and with selection control unit 4 via interrupt unit 18. 
     The user now acoustically enters the desired destination to be dialled in the form of words and/or numbers, by speaking into the receiver microphone of telephone station 32. The voice signal is processed in voice recognition unit 6 by comparing the similarity of a spoken word (number) with stored reference pattern data. The storage location number of the most similar pattern addresses the associated subscriber name (number) in a name directory, and the subscriber number to be dialled is read out of a directory store associated to this name directory. Selection control unit 4 advances the coded subscriber number signals to dialling unit 22 via first interface 10; dialling unit 22 then initiates conversion into dialling signals that can be processed by the exchange. Since dialling unit 22 contains a module for the dial-pulsing dialling method (DPM) as well as a module for the multi-frequency code dialling method (MFC), either dialling method can be employed, as desired. 
     As soon as the dialling process has been completed, selection control unit 4 again re-connects telephone station 32 back with the exchange, via first, second and third switching members 34, 36, and 38 of switching unit 12, and opens first switch 30, thereby permitting the user to conduct the desired call. 
     Selection control unit 4 is now in a wait status, with the hook status being sensed by the attached loop monitor-monitoring unit 28 (&#34;off-hook&#34;, as opposed to &#34;on-hook&#34;) and grounding key monitoring unit 26. Upon completion of the call (receiver on-hook), which is signaled by loop monitoring unit 28, selection control unit 4 returns to its initial status. If, however, the grounding or hold 24 is actuated in a P.A.B.X. system for the purpose of forwarding the call, for example, which is detected by grounding key monitoring unit 26 or loop monitoring unit 28 the same procedures described at the outset (beginning with line status identification logic unit 20) are again controlled by selection control unit 4. 
     In the facility according to the present invention, a connection can be established in a &#34;conventional&#34; manner at any time by manually entering the subscriber number by means or a dial or a keypad on telephone station 32, without the employment of voice-controlled additional facility 2. 
     Connection unit 14 has an interrupt unit 18 for this purpose. Interrupt unit 18 contains a dial pulse decoder 40 and a multi-frequency decoder 42, which are attached to selection control unit 4 via an interrupt request unit 44. After the receiver of telephone station 32 is taken off-hook, the previously described processes are first performed. Actuation of the dial or the keypad by the user is then identified by the above-mentioned decoders 40 or 42. Selection control unit 4 now receives an interrupt command from interrupt request unit 44, thereby initiating immediate switch-back of telephone station 32 to the exchange via telephone line 16 by means of switching unit 12, as well as causing first switch 30 to break. The dialling signals can then be transmitted directly to the exchange, without loss. 
     A further advantage of the circuit arrangement according to the present invention is that a series circuit comprising a videotex modem 46 and a videotex monitoring unit 48 can be connected with a-conductor a and b-conductor b via a second switch 50 in connection unit 14. In this case, selection control unit 4 is connected with second switch 50 via first interface 10 and with a videotex decoder of a television set via a second interface 52. 
     By acoustically entering words and/or numbers via the receiver microphone of telephone station 32, it is possible for the user to call up the videotex service feature by means of a voice command. By entering a command, such as &#34;videotex,&#34; for example, which is processed by voice-controlled additional facility 2, selection control unit 4 then connects videotex modem 46 with telephone line 16 by means of second switch 50. Videotex modem 46 automatically dials the videotex exchange after the television set has been switched on. When videotex monitoring unit 48 determines that a connection has been established and signals this status to selection control unit 4, first switch 30 is broken again. 
     Voice recognition unit 6 now remains connected with telephone station 32 for &#34;voice control.&#34; The user enters his videotex control commands acoustically, in the form of words and/or numbers. The voice signal is processed in voice recognition unit 6 and compared with the stored reference patterns. The storage location number of the most similar pattern addresses an associated videotex code directory, whose content is read out and advanced to the videotex decoder of a television set via second interface 52. This initiates a control process when the videotex service is called up. Upon completion of the videotex service, selection control unit 4, and thus connection unit 14, are returned to their initial status. 
     In the event of a voltage failure of voice-controlled additional facility 2 or connection unit 14, the remaining functions of telephone station 32 are not impaired.