Abstract:
To enable the simple and satisfactory connection of a plurality of telephone sets, data communication devices and similar to a single telephone line. A telephone set comprises a telephone circuitry portion, connected to a telephone line via switching means; an external equipment terminal, connected to the telephone line via switching means; line capture detection means which detects capture of the telephone line by a device connected to the external equipment terminal; and control means, which causes the first switching means, to be disconnected while the line capture detection means detects line capture, causes the second switching means, to be disconnected while telephone line capture by the telephone circuitry portion is detected, and causes the switching means to all be in the connected state when neither line capture is detected.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a telephone set connected, for example, to general subscriber telephone lines, and in particular relates to a telephone set designed such that other external equipment can be connected to the telephone set.  
           [0003]    2. Description of the Related Art  
           [0004]    A terminal part called a modular jack is connected to the telephone lines laid in ordinary houses and similar; by connecting this modular jack with the modular plug at the other end of the telephone line one end of which is connected to a telephone set, the telephone set is connected to the telephone line. A plurality of telephone sets can be connected to a single telephone line, and branch devices and similar are provided in order to form branches in this single telephone line. In addition to telephone sets for voice communication, equipment connected to the telephone line includes fax devices and modems for data communication; due to the spread of these devices, situations in which numerous devices are connected to a single telephone line have become widespread.  
           [0005]    However, when a telephone set for voice communication and a fax device or modem for data communication are connected to a single telephone line, if these devices are connected in parallel to the telephone line, when data communication is performed using the fax device or modem for data communication, if the receiver of the telephone set for voice communication is lifted, or there is some other off-hook operation, the telephone set circuit is connected to the telephone line during data communication, a communication error occurs, and data communication is interrupted.  
           [0006]    In the past, in order to solve such problems, it was conceivable to use what is called an automatic converter as a device which branches a single telephone line. For example, when this automatic converter is used to connect a two devices—a telephone set for voice communication, and a fax device—to a single telephone line, while one of the devices is in use, this equipment causes the telephone line to the other device to be disconnected.  
           [0007]    [0007]FIG. 5 shows the internal circuitry configuration of automatic converters of the prior art. Here, the automatic converter  90  is the type enabling connection of two devices, and comprises a modular jack  91  connected to an office line modular plug  81  which is connected to the exchange side of the telephone central office, and two modular jacks  92 ,  93  connected to modular plugs  82 ,  83  which are connected to a telephone set and other equipment. One of the lines L 1  among the two lines (L 1 , L 2 ) connected to the modular jack  91  is branched into two, and one of these branch lines is connected to the first line capture detection circuit  98  and the modular jack  92  via the switch  94 , while the other branch line is connected to the second line capture detection circuit  99  and the modular jack  93  via the switch  96 .  
           [0008]    The other line L 2  is branched into two, and one of these branch lines is connected to the modular jack  92  via the switch  95 , while the other branch line is connected to the modular jack  93  via the switch  97 .  
           [0009]    The switches  94 ,  95  connected to the modular jack  92  are configured such that opening and closing is controlled by the second line capture detection circuit  99  connected to the line on the side of the modular jack  93 , and the switches  96 ,  97  connected to the modular jack  93  are configured such that opening and closing is controlled by the first line capture detection circuitry  98  connected to the line on the side of the modular jack  92 .  
           [0010]    As the configuration of the first line capture detection circuitry  98 , here a connected configuration is assumed in which a diode bridge comprising four diodes D 1 , D 2 , D 3 , D 4  is connected to the line, and signals flowing in this line are extracted by the diode bridge, flow through a first and second control element PR 1 , PR 2  via a resistor R 1 , and return to the line from the diode bridge. A resistor R 2  is connected in parallel with the first and second control elements PR 1 , PR 2 , and a Zener diode ZD 1  is connected to set the voltage applied to both the control elements PR 1 , PR 2  within a fixed range. The first control element PR 1  controls the opening and closing of the switch  97 ; the second control element PR 2  controls the opening and closing of the switch  96 . The respective control elements PR 1 , PR 2  exercise control such that, when a current occurs corresponding to the signal flowing in the line at the time of line capture, the switches  96 ,  97  are in the open state, and when this current does not occur, they are in the closed state.  
           [0011]    The configuration of the second line capture detection circuitry  99  is the same as that of the first line capture detection circuitry  98 ; a diode bridge comprising four diodes D 5 , D 6 , D 7 , D 8  is connected to the line, and signals flowing in this line are extracted by the diode bridge, flow into third and fourth control elements PR 3 , PR 4  via a resistor R 3 , and return to the line from the diode bridge. A resistor R 4  is connected in parallel with the third and fourth control elements PR 3 , PR 4 , and a Zener diode ZD 2  is connected to set the voltage applied to both the control elements PR 3 , PR 4  within a fixed range. The third control element PR 3  controls the opening and closing of the switch  95 ; the fourth control element PR 4  controls the opening and closing of the switch  94 . The respective control elements PR 3 , PR 4  exercise control such that, when a current occurs corresponding to the signal flowing in the line at the time of line capture, the switches  94 ,  95  are in the open state, and when this current does not occur, they are in the closed state.  
           [0012]    Through this configuration, when neither of the devices (here assumed to be telephone sets) connected to the two modular jacks  92 ,  93  provided for this automatic converter is being used, all the switches  94 ,  95 ,  96 ,  97  are in the closed state, and the two telephone sets connected to the two modular jacks  92 ,  93  are in a state of connection to the office line connected to the modular jack  91 , so that two telephone sets can be made to ring by ringing signals from the telephone central office.  
           [0013]    When for example there is an off-hook operation in response to this ringing at the telephone set connected to one of the modular jacks  92 , and the line is captured, the line capture is detected by the first line capture detection circuitry  98  connected to this modular jack  92 , the switches  96 ,  97  connected to the modular jack  93  are put into the open state, and the telephone set connected to the modular jack  93  is disconnected from the telephone line. In the event of line capture by the telephone set connected to the other modular jack  93 , line capture is detected by the second line capture detection circuitry  99 , the switches  94 ,  95  connected to the modular jack  92  are put into the open state, and the telephone set connected to the modular jack  92  is disconnected from the telephone line.  
           [0014]    Hence, while one of the two telephone sets connected to this automatic converter  90  is in use, the other telephone set is disconnected from the telephone line, so that there can be no interruption in the telephone line by the other telephone set when one telephone set is in use, and in the case of a telephone set for voice communication, the contents of the voice communication cannot be heard from the other telephone set, so that a so-called confidentiality function is obtained. Further, when a fax device or modem device is connected in place of a telephone set, cutoff of the data communication performed by these devices due to interruption by another telephone set is prevented.  
           [0015]    However, if such an automatic converter is provided, the need arises to connect an extra device between telephone sets and telephone lines, and there is the problem that labor is required for connection. Further, because line capture must be detected within the automatic converter, line capture circuitry is connected; but if such a detection circuitry is connected 1  to the telephone line, a corresponding load is then connected to the telephone line, and there are problems such as a decrease in data transmission rate and decline in audio quality during voice communication.  
           [0016]    This invention was devised in light of these circumstances, in order to enable the simple and satisfactory connection of a plurality of telephone sets, data communication devices, and similar to a single telephone line.  
         SUMMARY OF THE INVENTION  
         [0017]    In order to solve these problems, in this invention, a telephone set comprises a telephone circuitry portion which is connected to a telephone line via a first switching means; an external equipment terminal which is connected to the telephone line via a second switching means; line capture detection means for detecting the capture of a telephone line by equipment connected to the external equipment terminal; and, control means, which causes the first switching means to be disconnected while the line capture means detects line capture, and which causes the second switching means to be disconnected while the telephone circuitry portion detects telephone line capture, and which causes both of the switches to be in the connected state when neither of the respective line capture [states] is detected.  
           [0018]    By providing the telephone set of this invention, upon connecting this telephone set t 2 o a telephone line, by for example connecting a fax device or modem device for data communication to the external equipment terminal, when the telephone line is used by the equipment connected to this external equipment terminal, the telephone circuitry portion of the telephone set is disconnected from the telephone line, a state is entered in which voice communication using this telephone set is not possible during data communication, and the occurrence of problems such as communication errors caused by interruption by this telephone set can be prevented. Further, when the telephone line is used by the telephone circuitry portion of the telephone set, the equipment connected to the external equipment terminal is disconnected from the telephone line, so that there is no interruption by other equipment of communication using this telephone set, and problems such as a decline in audio quality can be prevented. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a block diagram showing an example of a telephone set of one embodiment of this invention;  
         [0020]    [0020]FIG. 2 is a perspective view showing an example of the external appearance of the telephone set of one embodiment of this invention;  
         [0021]    [0021]FIG. 3 is a flow chart showing an example of operation during data communication of one embodiment of this invention;  
         [0022]    [0022]FIG. 4 is a flow chart showing an example of operation during voice communication of one embodiment of this invention; and  
         [0023]    [0023]FIG. 5 is a block diagram showing one example of a telephone line automatic converter of the prior art. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0024]    Below an embodiment of the invention is explained, referring to the attached figures.  
         [0025]    [0025]FIG. 1 is a drawing showing an example of the overall configuration of a telephone set of this example. In this example, a telephone set is connected to a wire telephone line, which is an office line connected with the telephone central office, and comprises a line modular jack  11  for connection to a modular plug  31  on the office line side, connected to an end of the line comprised by the telephone line. [The telephone set] further comprises a data communication modular jack  27 , as an external equipment terminal for connection of equipment other than this telephone set to the telephone line. Here the jack  27  is stated to be for data communication; however, equipment which can be connected is not limited to modem devices or other data communication equipment, and various types of equipment which can be connected to telephone lines, such as ordinary telephone sets and fax devices, can be connected. In the example of FIG. 1, the modem of a computer device  32  is connected to the data communication modular jack  27 .  
         [0026]    The telephone set  10  of this example is a telephone set to which a handset  20  is connected, and for which voice communication is possible using this handset  20 . That is, the two lines L 1 , L 2  connected to the line modular jack  11  are connected to the telephone circuitry portion  14  via separate switches  12 ,  13 , and a speaker  21  and microphone  22  incorporated into the handset  20  are connected to this telephone circuitry portion  14 . In the telephone circuitry portion  14 , sending and receiving processing for telephone communication are performed, based on the control of the central processing unit (CPU)  15  which controls the operation of each portion of the telephone set  10 . By assuming the open state, the switches  12 ,  13  disconnect the telephone circuitry portion  14  from the telephone line; control of the switch opening and closing is executed by the CPU  15 . The two switches  12 ,  13  controlled by this CPU  15  comprise, for example, a semiconductor switch using a photo-MOS relay. A hook switch  23  is provided in the area where the handset  20  of the telephone set  10  of this example is placed, and the state of this hook switch  23  is detected by the CPU  15 .  
         [0027]    The telephone set  10  of this example is provided with functions for use as the master unit of a cordless telephone, and to this end comprises a wireless circuitry portion  16 . Signals obtained from the telephone line by the telephone circuitry portion  14  are wirelessly transmitted to the slave unit (not shown) from the antenna  17  connected to the wireless circuitry portion  16 , and signals sent from the slave unit and received by the antenna  17  are received and processed by the wireless circuitry portion  16  and can be sent to the telephone circuit. Wireless communication with the slave unit using this wireless circuitry portion  16  is executed under control by the CPU  15 .  
         [0028]    The telephone set  10  of this example comprises a display portion  18  which displays telephone numbers, names, functions, and similar using numerals, characters, symbols and similar under control of the CPU  15 , and keys  19  which indicate telephone numbers and similar to the CPU  15 .  
         [0029]    Next, the configuration between the line modular jack  11  and the modular jack  27  for data communication in the telephone set  10  of this example is explained. The two lines L 1 , L 2  connected to the line modular jack  11  are branched separately from the switches  12 ,  13 , and are connected to the modular jack  27  for data communication via the respective switches  24 ,  25 . By assuming the open state, the switches  12 ,  13  disconnect the telephone circuitry portion  14  from the telephone line; for example, [these switches] may comprise a semiconductor switch using a photo-MOS relay, and opening and closing are controlled by the CPU  15 . Light-emitting diodes D 11 , D 12  within a photocoupler  26  are connected between one of these switches  25  and the jack  27 . This photocoupler  26  constitutes telephone line capture detection means; the two light-emitting diodes D 11 , D 12  are connected in opposite directions, and emit light whatever the direction of signal flow.  
         [0030]    When either of the light-emitting diodes D 11 , D 12  within the photocoupler emits light above a fixed level, the phototransistor Q 11  is turned on, and the CPU  15  detects this. In the case of this example, when the telephone line connected to the jack  11  is captured by a device (in the example of FIG. 1, the modem of a computer device  32 ) connected to the modular jack  27  for data communication, the phototransistor Q 11  is turned on, and the CPU  15  is capable of judging this.  
         [0031]    Each of the circuits in the telephone set  10  of this example operates using a power supply which is, for example, a low-voltage DC power supply obtained by rectification and transformation of a commercial AC power supply.  
         [0032]    [0032]FIG. 2 shows one example of the shape of the telephone set  10  of this example. In the telephone set  10  of this example, the line modular jack  11  and the modular jack  27  for data communication are positioned, as jacks for connection, on a side face or similar of the telephone set body. The display  18  is designed to display various operating states in addition to displaying telephone numbers with a prescribed number of digits. Here “External terminal in use” is displayed in characters, indicating the state in which the data communication in-use display  18   a  is executed. This data communication in-use display  18   a  is performed when the CPU  15  within the telephone set judges that line capture is performed by the modular jack  27  for data communication.  
         [0033]    Next, an example of a state in which the CPU  15  of this example controls the switches  12 ,  13  connected to the telephone circuitry portion  14  and the switches  24 ,  25  connected to the modular jack  27  for data communication is explained, referring to the flow charts of FIG. 3 and FIG. 4.  
         [0034]    Each of the switches  12 ,  13 ,  24 ,  25  is designed so as to be in the closed state while in the initial state. Hence in this initial state, calls by the telephone line can be detected by the telephone circuitry portion  14  within the telephone set  10 , and when some kind of telephone set is connected to the modular jack  27  for data communication, calls by the telephone line can also be detected even by the connected telephone set, and calling from each of the devices (telephone sets) is also possible.  
         [0035]    When telephone line capture by a device connected to the modular jack  27  for data communication is detected by the photocoupler  26  which is the telephone line capture detection means, the CPU  15  controls the switches  12 ,  13 . The flow chart of FIG. 3 shows the control operation at this time. The explanation below follows FIG. 3; based on the detection output from the photocoupler  26 , the CPU  15  judges whether or not there is telephone line capture by the device connected to the modular jack  27  for data communication (step  101 ). If line capture is not detected, [the CPU] waits without further action. If telephone line capture is detected, the switches  12 ,  13  are put into the open state under control of the CPU  15 , and the telephone circuitry portion  14  is disconnected from the telephone line connected to the jack  11  (step  102 ).  
         [0036]    After putting these switches  12 ,  13  into the open state, the CPU  15  judges the detection output from the photocoupler  26 , and judges whether line capture is ended or not (step  103 ). If the end of line capture is not detected, [the CPU] waits while keeping the switches  12 ,  13  in the open state. If it is judged that line capture has ended, the switches  12 ,  13  are put into the closed state, and the telephone circuitry portion  14  is connected to the telephone line (step  104 ). After putting the switches  12 ,  13  into the closed state, execution returns to the judgment of step  101 .  
         [0037]    Next, the state of control when the telephone circuitry portion  14  of the telephone set  10  of this example is used is explained, referring to the flow chart of FIG. 4. At this time, a judgment is made as to whether the off-hook state is entered due to operation of a hook switch  23  (or reception of a hook switch operation signals from the slave device by the wireless circuitry portion  16 ). If the off-hook state is not detected, [the CPU] waits without further action. If the off-hook state is detected, the switches  24 ,  25  are put into the open state under control of the CPU  15 , and the device connected to the modular jack  27  for data communication is disconnected from the telephone line connected to the jack  11  (step  112 ).  
         [0038]    After these switches  24 ,  25  are put into the open state, the CPU  15  judges the state of the hook switch  23  and of the state of reception of hook switch operation signals from the slave unit at the wireless circuitry portion  16 , and judges whether there has been a change from the off-hook state to the on-hook state (step  113 ). If a change to the on-hook state is not detected, [the CPU] waits with the switches  24 ,  25  left in the open state. When it is judged that there has been a change to the on-hook state, the switches  24 ,  25  are put into the closed state, and the device connected to the modular jack  27  for data communication is connected to the telephone line connected to the jack  11  (step  114 ). After putting these switches  24 ,  25  into the closed state, execution returns to step the judgment of  111 .  
         [0039]    By thus controlling each of the switches, when for example a computer or other data communication device is connected to the modular jack  27  for data communication of the telephone set  10  of this example, if there is an off-hook operation by the handset  20  or slave unit of this telephone set  10 , during voice communication by this telephone set  10  the switches  24 ,  25  are in the open state, and the data communication device connected to the modular jack  27  is disconnected from the telephone line, so that there is no interruption during voice communication by data communication from the device connected to the jack  27 , and the quality of voice communication can be improved.  
         [0040]    Also, when performing data communication using a device connected to the modular jack  27  for data communication, the switches  12 ,  13  are in the open state and the telephone circuitry portion  14  is in a state disconnected from the telephone line, so that there is no interruption during data communication by audio communication signals, and the occurrence of data communication errors can be effectively prevented. In this example, data communication in-use display  18   a  such as shown in FIG. 2 is shown on the display  18  of the telephone set  10 , so that it can be reliably understood from the display that the telephone line cannot be used from this telephone set  10 ; for example, a user who does not know that data communication is in progress will not mistakenly conclude that the telephone set is out of order.  
         [0041]    As the detection means to perform this processing, a photocoupler  26  connected between the switch  25  and the modular jack  27  is used with respect to communication by the device connected to the modular jack  27 ; in addition to being designed for electrical non-contact detection, this photocoupler  26  is disconnected from the telephone circuit when the switches  24 ,  25  are in the open state, and so is not connected as a load to the telephone circuit connected to the telephone circuitry portion  14 , and a decline in voice communication quality due to connection of extra circuitry during voice communication can be prevented.  
         [0042]    With respect to detection of capture of the telephone line by this telephone set  10 , the CPU  15  makes judgments based on hook operation signals from the hook switch and slave unit, so that there is no need for means to detect line capture from the state of the line connected to the telephone line, and increases in load due to connection of extra equipment during communication by equipment connected to the modular jack  27  can also be effectively prevented.  
         [0043]    When the modular jack  27  for data communication of this telephone set  10  is used to install data communication equipment or other telephone sets, it is sufficient to connect in order two devices from the telephone line side, and there is no need for an automatic converter like that shown in FIG. 5 as in the example of the prior art, so that the connected configuration can be simplified.  
         [0044]    In the example shown in FIG. 1, the modem of a computer device is connected to the modular jack  27  for data communication; however, similar functions and similar effects result when a telephone set is connected to the jack  27 . [This invention] can also be applied in cases where the telephone set  10  incorporates fax device or other functions, and is provided with functions for fax communication or other data communication.  
         [0045]    In the above-described embodiment, as the switches  12 ,  13 ,  24 ,  25  to cut off lines, semiconductor switches using photo-MOS relays were employed; however, switches having mechanical contacts may be used to configure relays which operate similarly.  
         [0046]    In the above-described embodiment, detection of line capture for voice communication within the telephone set body is performed from hook operation signals from the hook switch or slave unit; however, the CPU  15  may instead judge the state within the telephone circuitry portion  14  and detect capture of the telephone line.  
         [0047]    Having described preferred embodiments of the present invention with reference to the accompanying drawings, it is to be understood that the present invention is not limited to the above-mentioned embodiments and that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit or scope of the present invention as defined in the appended claims.