Abstract:
A telephony device is formed by a base station and subscriber units. The telephony device includes a responder circuit formed predominantly by a flash memory located in the base station. The responder circuit has various states: on line, in service, in possession or not of a message . . . etc. These states may be displayed on the screens of all the subscriber units by a broadcast of messages transmitted from the base station.

Description:
FIELD OF THE INVENTION 
     The invention relates to a telephony device comprising a base station connected to the switched network, at least a subscriber unit and at least a communication element of the responder type, notably linked with the base station which has a management element formed, inter alia, by a processor assembly, by a memory containing an execution program and by a random-access memory. 
     The invention likewise relates to a method used in such a telephony device and also relates to a subscriber unit suitable for such a telephony device. 
     The invention finds interesting applications in telecommunication systems implying protocols which is notably the case with telephony devices satisfying the DECT standard, for example. 
     BACKGROUND OF THE INVENTION 
     The telephony devices of this type very often comprising numerous subscriber units offer more and more functions to the user. One of these functions is that of the responder which makes it possible to receive and transmit messages for those who call and which authorize the return of messages to the user at his request. 
     A problem posed with this type of device is for the user who may be located far from the base station to know whether he has messages. The user may also have the need to make an announcement and thus desires to know whether his responder is available. This problem is all the more serious when one faces devices that satisfy the DECT standards which may thus comprise a large number of subscriber units. 
     SUMMARY OF THE INVENTION 
     The present invention proposes a device of the type defined in the opening paragraph which permits a user to manage in an easy fashion the accesses to the responder inserted into the base station. 
     Therefore, such a device is characterized in that data about the state of the communication element is broadcast to all the subscriber units. 
     The idea of the invention consists of utilizing the possibility of broadcasting data to all the subscriber units so as to make known to them the state of their responder and, possibly, communicating with them. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. 
     In the drawings: 
     FIG. 1 shows a device according to the invention, 
     FIG. 2 shows a diagram explaining the operation of the base station, and 
     FIG. 3 shows a diagram explaining the operation of a subscriber unit. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     In FIG. 1, the device which is represented is a device satisfying the DECT standards. Reference  1  shows the base station BS to which may be connected, by radio channel, a plurality of subscriber units (handsets) HS 1 , HS 2 , . . . This base station  1  comprises, inter alia, a line circuit  10  which makes it possible for connecting the base station to the switched network by a telephone line  12  and a radio circuit  14  which authorizes the dialogue with the various subscriber units HS 1 , HS 2 , . . . , by emitting and receiving waves via an antenna  16 . For processing all the analog information which transits the basic circuit, a signal processing element  15  is provided formed around a digital signal processor DSP which processes notably the speech signals. A flash memory  17  is used for performing the function of responder. That is to say that it contains the speech data coming from remote subscribers through line  12  and also announcement data which are more often than not intended for these remote subscribers. The data of this memory  17  are processed by the circuit  15  which carries out the various analog/digital conversions and vice versa. 
     All the elements of this basic circuit  1  are managed by a microprocessor assembly  20 . This assembly is formed, notably, in usual manner by a random-access memory  24 , a read-only memory  26  containing the instructions and operation of the device and a management processor  29 . With this assembly it is possible to know when the flash memory  17  which is the main constituent part of the responder function is available or not and if a message has been registered there or not. 
     The subscriber unit HS 1 , only shown in detail (the unit HS 2  may have an identical structure) comprises a communication assembly  40  with an antenna  41  which permits the unit to communicate with the base station BS and from there with the other subscriber units HS 2 , . . . This assembly processes the information coming from the microphone  42  and also produces signals for an earphone  44 . Also provided is a management element  50  formed, just like the management element  20 , by a random-access memory  54 , a read-only memory  56  containing the operating instructions of the device, and by a management processor  59 . The subscriber unit HS 1  also has a screen  60  on which the various data are displayed and a keyboard  61 . These handsets are mobiles and because of this they are fed by an accumulator not shown on the FIG.  1 . 
     According to the invention, the state of the responder circuit is shown on the screen  60  without the intervention of the user. This is achieved due to an interesting characteristic feature of the invention by realizing a message broadcast. For this purpose, the prescriptions of the paragraph 7.2.4.3 of the ETS standard 300 175-3 are used. 
     The Table I below shows how this standard is used. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE I 
               
               
                   
                   
               
               
                   
                 Data 
                 binary word 
               
               
                   
                   
               
             
             
               
                   
                 Responder in service 
                 M1 =  0111 0011 0000 0001 
               
               
                   
                 Responder not in service 
                 M1′ = 0111 0011 0000 0000 
               
               
                   
                 Registered messages 
                 M2 =  0111 0011 0000 0010 
               
               
                   
                 No messages 
                 M2′ =  0111 0011 0000 0011 
               
               
                   
                 Aligned responder 
                 M3 =  0111 0011 0000 0100 
               
               
                   
                 Non-aligned responder 
                 M3′ =  0111 0011 0000 0101 
               
               
                   
                   
               
             
          
         
       
     
     Thus, word pairs are found which are mutually exclusive. M 1  and M 1 ′ are mutually exclusive as are the pairs M 2 , M 2 ′ and M 3  and M 3 ′. These words are explained at the places referenced a 32  to a 47  of said standard. 
     In FIG. 2 are explained the operation steps of the responder circuit. 
     The state ST 1  is considered which indicates that the responder is not in service, thus the word M 1 ′ is transmitted in the direction of all the subscriber units. If the responder is put into operation, for example, by validating this start which appears on a menu visible on a screen of the base station, then state ST 2  is proceeded to, the word M 1  is thus transmitted. After that, the responder may be aligned, state ST 3  corresponding to the transmission of the word M 3  for carrying out a task such as: registering a message which comes from the telephone line  12 , broadcasting an announcement over this telephone line  12  or also returning a message to a user on one of the subscriber units. Having performed its task, the responder changes to the state ST 4  corresponding to the transmission of the word M 3 ′ by passing either through the state ST 5  which indicates that no message has been registered during the alignment, or by passing through state ST 6  which indicates that a message has been registered. The states ST 5  and ST 6  imply the transmission of the words M 2 ′ and M 2 , respectively. It is evident that from each of these states one may come back to the state ST 1  by deactivating the responder function. 
     Starting from a subscriber unit, one may consult the state of this responder circuit by validating certain items of a menu. This is shown in a diagram in FIG.  3 . 
     If the word M 1 ′ has been transmitted, which is detected in box K 1 , thus signaling that the responder is not in service, only this data M 1 ′ is visible to the user. He is thus shown that the responder is not in service (box K 2 ). If the word M 1  has been transmitted, then the data concerning the words M 1 , M 2  or M 2 ′, M 3  or M 3 ′ are visible (box K 3 ). 
     These various words are transmitted periodically, so that, if a subscriber unit is no longer in the coverage area of the base station, the state data concerning the responder will be updated the moment the subscriber unit will come back to said coverage area. 
     However, it should be observed that the words M 1 ′ and M 2  are not exclusive. Indeed, it may happen that the user has: 
     put his responder into operation, transmission of the word M 1 , 
     received messages, transmission of the word M 2 , 
     put his responder out of operation, without reading the messages, transmission of the word M 1 ′. 
     In this case, the words M 2  and M 1 ′ will be transmitted at the moment of the change of state and after that periodically. And the data corresponding to the words M 2  and M 1 ′ will have to be visible.