Communication terminal and control method for communication terminal

Abstract

To provide a communication terminal that is equipped with a handset and can appropriately start a call of a PTT method regardless of the presence or absence of a PTT button of a connected handset or an external audio input / output set.SOLUTION: A call control unit (71) performs control to start a PTT call in response to detection of PTT on by a PTT detection unit (74) after a handset (20) is off-hooked and the PTT detection unit (74) detects PTT off.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] One aspect of the present invention relates to a communication terminal and a method for controlling the communication terminal. relates to.

Background Art

[0002] Conventionally, in a radio, it has been possible to wear a headset equipped with a speaker and a microphone. For example, Patent Document 1 discloses a radio that can be connected to an external input device having an external PTT switch, an external microphone, and an external speaker, and has a built-in microphone and a transmission means.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] RJ-9 (registered jack) and RJ-11 standard connectors used in stationary communication terminals are four-wire types. Therefore, in order to use a headset equipped with a PTT button, the operation of the PTT button on the headset side needs to be configured to be linked to the switch opening and closing of the input signal line from the microphone on the headset side. In this case, there is no difference in the conduction state of the circuit between the state where the PTT is turned on by pressing the PTT button on the headset side and the state where a headset is connected such that the input signal line directly from the microphone is connected to the main body of the communication terminal without passing through the PTT button.

[0005] Therefore, in a communication terminal equipped with a handset, when there is a possibility that both a headset equipped with a PTT button and a headset not equipped with a PTT button are connected, after the headset goes off-hook, there is a problem that it is impossible to appropriately determine that PTT on has been performed based on the conduction state of the above circuit.

[0006] One aspect of the present invention aims to realize a communication terminal that can appropriately start a PTT call in a communication terminal equipped with a handset, regardless of the presence or absence of a PTT button on the connected handset or external audio input / output set.

Means for Solving the Problems

[0007] To solve the above problems, a communication terminal according to one aspect of the present invention includes a PTT call processing unit that performs a PTT call by the PTT method, a call control unit that controls the call by the PTT call processing unit, an external connection terminal to which an external connection speaker and an external connection microphone are connected, a PTT detection unit that detects PTT on and PTT off by a PTT button connected via the external connection terminal, and a call instruction detection unit that detects a call start instruction and an end instruction from a user. The call control unit performs control to start the PTT call associated with the detection of PTT on by the PTT detection unit after the PTT off is detected by the PTT detection unit after the call instruction detection unit detects the start instruction.

Effects of the Invention

[0008] According to one aspect of the present invention, since the PTT call is started when PTT on is detected after PTT off is detected once, the PTT call can be appropriately started.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the present invention will be described in detail.

[0011] 〔Communication System〕 Hereinafter, an embodiment of the present invention will be described in detail.

[0012] 〔Communication System〕 FIG. 1 is a diagram showing an example of the configuration of a communication system 100 including a communication terminal 1 according to the present embodiment. In the example shown in FIG. 1, the communication system 100 includes a relay device 110, a communication terminal 1, and communication terminals 131, 132, 133, 134.

[0013] The communication terminal 1 is a communication terminal capable of making calls using multiple communication methods. Specifically, the communication terminal 1 has a PTT (Push to Talk) call function using an IP (Internet Protocol) network by the PTT method, and an IP phone call function by IP phone communication using SIP (Session Initiation Protocol). Note that, as will be described later, the connection of the communication terminal 1 to the IP network 121 may be made wired or wirelessly. In the following description, for convenience, communication by the PTT method is referred to as IP wireless communication, and a call by the IP wireless communication is referred to as an IP wireless call function. The communication terminal 1 is connected to the IP network 121 either wired or wirelessly and is connected to the relay device 110 via the IP network 121. The specific configuration of the communication terminal 1 will be described later. Note that communication by the PTT method is not limited to being via an IP network and may be performed via other types of communication networks.

[0014] The communication terminals 131 to 134 are communication terminals capable of communicating by IP wireless communication or IP phone communication. The communication terminal 131 is connected to the relay device 110 via the IP network 121 and performs IP wireless communication. The communication terminal 132 is connected to the relay device 110 via an LTE (Long-Term Evolution) communication network 122 having a base station (not shown) and performs IP wireless communication. The communication terminal 133 is connected to the relay device 110 via the IP network 121 and performs IP wireless communication and IP phone communication. The communication terminal 134 is connected to the relay device 110 via the LTE communication network 122 and performs IP wireless communication and IP phone communication.

[0015] The relay device 110 is a device in which a VoIP (Voice over Internet Protocol) gateway 111 and a network communication relay unit 112 are integrally configured. However, the communication system 100 does not necessarily need to include the relay device 110 in which the VoIP gateway 111 and the network communication relay unit 112 are integrated, and the VoIP gateway 111 and the network communication relay unit 112 may be provided separately.

[0016] The VoIP gateway 111 is a gateway device that relays the VoIP procedure for transmitting voice signals via the IP network 121 and the communication terminals for making telephone calls. The VoIP gateway 111 relays the IP telephone communication between the communication terminal 1 and the communication terminals 133 and 134. The communication terminal 134 is connected to the VoIP gateway 111 in the relay device 110 via the LTE communication network 122.

[0017] The VoIP gateway 111 incorporates the SIP (Session Initiation Protocol) server function. The SIP server function is a function that uses the SIP protocol to associate a telephone number (URI) with an IP address and perform call control to call and connect the telephone of the communication partner. However, the communication system 100 may be provided with an IP-PBX (Internet Protocol Private Branch eXchange) device that performs circuit switching of communication terminals having an IP telephone communication function instead of the VoIP gateway 111.

[0018] The network communication relay unit 112 relays the communication between the communication terminal 1 and the communication terminals 131 to 134. In particular, the network communication relay unit 112 relays the IP wireless communication between the communication terminal 1 and the communication terminals 131 to 134.

[0019] In addition, the network communication relay unit 112 receives the voice packets transmitted from the communication terminal 1 or the communication terminals 131 and 133. Further, the network communication relay unit 112 distributes the voice signal of this packet to the communication terminal 1 or the communication terminals 131 and 133 of the communication partner based on the communication control information written in the voice packet. As a result, the user can perform voice communication via the IP network 121 with the same feeling of use as a conventional transceiver.

[0020] Note that in the relay device 110, the VoIP gateway 111 and the network communication relay unit 112 may be connected so that a call can be made between a communication terminal performing IP telephone communication and a communication terminal performing IP wireless communication.

[0021] 〔Configuration of Communication Terminal〕 FIG. 2 is a plan view showing an example of the appearance of the communication terminal 1. FIG. 3 is a block diagram showing an example of the configuration of the main part of the communication terminal 1. In the examples shown in FIGS. 2 and 3, the communication terminal 1 includes a main body 10, a handset 20, and a cord 30. In FIG. 3, the cord 30 is omitted.

[0022] The main body 10 includes a main body side speaker 11 and a main body side microphone 12. The main body side speaker 11 outputs voice during a call made by the main body 10. The main body side microphone 12 receives voice input during a call made by the main body 10.

[0023] The main body 10 further includes a hook switch (call instruction detection unit) 13. The hook switch 13 is pressed when the handset 20 is on-hook and released when the handset 20 is off-hook. That is, the hook switch 13 is a switch for detecting whether the handset 20 is off-hook.

[0024] The main body 10 further includes a PTT button 14. The PTT button 14 is a button for starting a transmission by the PTT method. For example, the communication terminal 1 may start a transmission at the timing when the user presses the PTT button 14 and end the transmission at the timing when the user releases the PTT button 14. Alternatively, the communication terminal 1 may start a transmission at the timing when the user presses and releases the PTT button 14 and end the transmission at the timing when the user presses and releases the PTT button 14 again.

[0025] The main body 10 further includes a display unit 15. The display unit 15 displays information about the operation of the communication terminal 1. The display unit 15 may be a known display device such as a liquid crystal panel.

[0026] For example, when IP wireless communication is being performed, the display unit 15 displays information indicating that IP wireless communication is being performed. Also, when IP phone communication is being performed, the display unit 15 may display information indicating that IP phone communication is being performed. Thereby, the user can easily recognize in which mode the call is being made by checking the display unit 15.

[0027] In addition, when there is an incoming call for IP phone communication while IP wireless communication is being performed, or when there is a reception for IP wireless communication while IP phone communication is being performed, the display unit 15 displays to that effect.

[0028] The main body 10 further includes an instruction input unit 16. The instruction input unit 16 may be a button provided on the surface of the main body 10, but is not limited thereto. For example, the instruction input unit 16 may be a touch panel provided so as to overlap the display unit 15. The instruction input unit 16 receives an instruction input from the user to display at least any one of a call destination list, a reception or incoming call history, and a transmission or outgoing call history on the display unit 15.

[0029] When the above instruction input is received at the time when IP wireless communication is being performed, the display unit 15 may display at least any one of an address book, a reception history, and a transmission history related to IP wireless communication. Also, when the above instruction input is received at the time when IP phone communication is being performed, the display unit 15 may display at least any one of a phone book, an incoming call history, and an outgoing call history related to IP phone communication.

[0030] Generally, the address book or phone book, the reception or incoming call history, and the transmission or outgoing call history in communication are different from each other between IP wireless communication and IP phone communication. By having the display unit 15 display at least any one of the address book or phone book, the reception or incoming call history, and the transmission or outgoing call history as described above, it becomes possible to display on the display unit information corresponding to the communication method in which communication is being performed at that time.

[0031] The handset 20 includes a handset-side speaker (external connection speaker) 21, a handset-side microphone (external connection microphone) 22, and a handset-side PTT button 23 (see FIG. 3). The handset-side speaker 21 outputs sound during a call made by the handset 20. The handset-side microphone 22 receives an input of sound during a call made by the handset 20. During communication by the handset 20, the user may hold the handset 20 near his or her head such that the handset-side speaker 21 is positioned near the ear and the handset-side microphone 22 is positioned near the mouth. The handset-side PTT button 23 will be described later.

[0032] The cord 30 is a cord that connects the main body 10 and the handset 20. As for the cord 30, a known cord can be used without particular limitation.

[0033] Also, as shown in FIG. 3, a headset 90 can be connected to the communication terminal 1. The user can connect the headset 90 to the communication terminal 1 and make a call. The headset 90 includes a headset-side speaker (external connection speaker) 91, a headset-side microphone (external connection microphone) 92, and a headset-side PTT button 93. The headset-side speaker 91 outputs sound during a call made by the headset 90. The headset-side microphone 92 receives an input of sound during a call made by the headset 90. The headset-side PTT button 93 will be described later.

[0034] 〔Detailed Configuration of Main Body〕 A more detailed configuration of the main body 10 will be described below.

[0035] The main body 10 is provided with amplifiers 41, 42, 43, 44, 45, and 46. The amplifier 41 amplifies the audio signal output to the main body side speaker 11. The amplifier 42 amplifies the audio signal input from the main body side microphone 12. The amplifier 43 amplifies the audio signal output to the handset side speaker 21. The amplifier 44 amplifies the audio signal input from the handset side microphone 22. The amplifier 45 amplifies the audio signal output to the headset side speaker 91 when the headset 90 is connected to the communication terminal 1. The amplifier 46 amplifies the audio signal input from the headset side microphone 92 when the headset 90 is connected to the communication terminal 1. Note that the handset side speaker 21 and the headset side speaker 91 may be configured to be amplified by one amplifier, and the connection destination may be appropriately switched by a switch. Similarly, the handset side microphone 22 and the headset side microphone 92 may be configured to be amplified by one amplifier, and the connection destination may be appropriately switched by a switch.

[0036] The main body 10 further includes a main body side codec 51 and a handset side codec 52. The communication terminal 1 transmits and receives the audio signal in an encoded state. The main body side codec 51 decodes the audio signal received from the outside and outputs it to the main body side speaker 11. Also, the main body side codec 51 encodes the audio signal input from the main body side microphone 12.

[0037] The handset side codec 52 decodes the audio signal received from the outside and outputs it to the handset side speaker 21. Also, the handset side codec 52 encodes the audio signal input from the handset side microphone 22.

[0038] Furthermore, when the headset 90 is connected to the communication terminal 1 and the user communicates using the headset 90, the handset side codec 52 decodes the audio signal received from the outside and outputs it to the headset side speaker 91. Also, in this case, the handset side codec 52 encodes the audio signal input from the headset side microphone 92.

[0039] The main body 10 further includes an audio cancellation processing unit 60. The audio cancellation processing unit 60 removes the audio signals output to the main body side speaker 11 and the handset side speaker 21 from the audio signals input from the main body side microphone 12 or the handset side microphone 22. When a headset 90 is connected to the communication terminal 1, the audio cancellation processing unit 60 removes the audio signals output to the main body side speaker 11, the handset side speaker 21, and the headset side speaker 91 from the audio signals input from the main body side microphone 12, the handset side microphone 22, or the headset side microphone 92.

[0040] That is, howling prevention is achieved by preventing the output of the main body side speaker 11 from being input to the main body side microphone 12, and howling prevention is achieved by preventing the output of the handset side speaker 21 from being input to the handset side microphone 22. Further, even when IP phone communication is performed with the handset side microphone 22, in addition to the output from the handset side speaker 21, the output from the main body side speaker 11 is also input as an audio signal to be cancelled, thereby suppressing mixing into the call being made on the handset 20 side. Thereby, even when an audio signal is input from any of the main body side microphone 12, the handset side microphone 22, or the headset side microphone 92, the quality of the audio signal transmitted to the outside can be improved.

[0041] The main body 10 further includes a control unit 70. The control unit 70 controls the operation of the communication terminal 1. The control unit 70 includes a call control unit 71, an IP wireless processing unit (PTT call processing unit) 72, an IP phone processing unit 73, and a PTT detection unit 74.

[0042] The IP wireless processing unit 72 performs IP wireless communication in the PTT method via the IP network 121. The IP phone processing unit 73 performs IP phone communication by SIP via the IP network 121. The call control unit 71 controls the calls by the IP wireless processing unit 72 and the calls by the IP phone processing unit 73.

[0043] Specifically, when the handset 20 goes off-hook, if IP wireless communication is being performed by the main body side speaker 11 and the main body side microphone 12, the call control unit 71 controls the call by the IP wireless processing unit 72 so that IP wireless communication is performed by the handset 20. Here, the "case where IP wireless communication is being performed" refers to being in a call by IP wireless communication or being within a predetermined time after receiving voice by IP wireless communication. The predetermined time may be a length of time generally assumed as a blank time during a call, for example, 5 seconds. Also, when the handset 20 goes off-hook and IP wireless communication is not being performed, the call control unit 71 controls the call by the IP phone processing unit 73 so that an IP phone call by SIP is performed by the handset 20.

[0044] By the above control, in the communication terminal 1, depending on whether IP wireless communication is being performed when the handset 20 goes off-hook, it is switched whether a call by IP wireless communication or a call by IP phone communication is performed by the handset 20. Therefore, the user can make a call in an appropriate call mode only by the operation of taking the handset 20 off-hook. In this case, the IP wireless communication continues until the handset 20 is next put on-hook.

[0045] Also, when the handset 20 goes off-hook and neither IP wireless communication nor IP phone communication is being performed, the call control unit 71 causes the handset side speaker 21 to output a dial tone (DT) sound in IP phone communication. Further, when the PTT button 14 is pressed in this state, the call control unit 71 starts IP wireless communication.

[0046] With the above control, when the handset 20 is off-hooked in the communication terminal 1 in a state where neither IP wireless communication nor IP telephone communication is being performed, it first stands by in a state where IP telephone communication can be started. Then, when the PTT button 14 is pressed, IP wireless communication is started. Also in this case, the IP wireless communication continues until the handset 20 is on-hooked next.

[0047] Therefore, when the user wants to make an IP telephone call, simply off-hooking the handset 20 and entering the telephone number of the called party etc. will suffice. On the other hand, when the user wants to perform IP wireless communication, they just need to off-hook the handset 20 and press the PTT button. That is, the user can start a call in the desired mode with natural operations.

[0048] Also, as described above, when there is an incoming call for IP telephone communication while IP wireless communication is being performed, or when there is a reception for IP wireless communication while IP telephone communication is being performed, the display unit 15 displays that fact. At this time, the call control unit 71 may switch from IP wireless communication to IP telephone communication, or from IP telephone communication to IP wireless communication, in response to an instruction input from the user. Thereby, when there is an incoming call for IP telephone communication while IP wireless communication is being performed, or when there is a reception for IP wireless communication while IP telephone communication is being performed, the user can change to the desired mode based on the display on the display unit.

[0049] The control unit 70 is not limited to the processing by the call control unit 71, the IP wireless processing unit 72, the IP telephone processing unit 73, and the PTT detection unit 74, and comprehensively controls the operation of the communication terminal 1. For example, the control unit 70 controls the display unit 15 to display the above-described information.

[0050] The main body 10 further includes a storage unit 80. The storage unit 80 is a storage device that stores information required by the control unit 70 in the control of the communication terminal 1. However, in the communication terminal 1, the storage unit 80 is not essential. When the communication terminal 1 does not include the storage unit 80, the communication terminal 1 may be communicably connected to an external storage device.

[0051] The headset-side speaker 91 and the headset-side microphone 92 in FIG. 3 are examples of an external connection speaker and an external connection microphone in the communication terminal 1, respectively. As shown in FIG. 3, the communication terminal 1 includes an external connection terminal 47 for connecting the headset-side speaker 91 and the headset-side microphone 92. In addition, the communication terminal 1 includes an external connection terminal 48 for connecting the handset-side speaker 21 and the handset-side microphone 22.

[0052] As described above, the headset 90 includes a headset-side PTT button 93. As shown in FIG. 3, the headset-side PTT button 93 is connected to the amplifier 46 via the external connection terminal 47. In this way, the headset-side PTT button 93 is an example of a PTT button connected to the communication terminal 1 via the external connection terminal 47. Note that the headset 90 does not necessarily include the headset-side PTT button 93, and a configuration that does not include the headset-side PTT button 93 may be used.

[0053] The headset-side PTT button 93 is interposed between the external connection terminal 47 and the headset-side microphone 92. The headset-side PTT button 93 is a button for starting a speech by the PTT method. In the configuration of the present embodiment, the connection state between the external connection terminal 47 and the headset-side microphone 92 is switched. In other words, the headset-side PTT button 93 switches the connection state between the amplifier 46 and the headset-side microphone 92. In this way, the headset-side microphone 92 is connected to the amplifier 46 via the headset-side PTT button 93.

[0054] In the example of FIG. 3, the handset 20 further includes a handset-side PTT button 23. The handset-side PTT button 23 is an example of a PTT button provided on the handset 20. The handset-side PTT button 23 is interposed between the amplifier 44 and the handset-side microphone 22 via the external connection terminal 48. The handset-side PTT button 23 switches the connection state between the amplifier 44 and the handset-side microphone 22. Thus, the handset-side microphone 22 is connected to the amplifier 44 via the handset-side PTT button 23. Note that it is not essential for the handset 20 to include the handset-side PTT button 23, and a configuration without the handset-side PTT button 23 may be used. Also, the handset 20 and the main body 10 may be directly connected without passing through the external connection terminal 48.

[0055] As described above, the control unit 70 includes a PTT detection unit 74. The PTT detection unit 74 detects PTT on and PTT off by at least one of the headset-side PTT button 93 and the handset-side PTT button 23. PTT on means a state in which the PTT button is pressed. In other words, PTT on means that the microphone corresponding to the PTT button is in a conductive state. On the other hand, PTT off means a state in which the PTT button is not pressed. In other words, PTT off means that the microphone corresponding to the PTT button is in a non-conductive state.

[0056] The call control unit 71 in the example of FIG. 3 determines whether the handset 20 is in an off-hook state (hereinafter referred to as the off-hook state). The off-hook state indicates a state in which the handset 20 is lifted by the user and not hooked to the hook switch 13. On the other hand, the on-hook state indicates a state in which the handset 20 is placed while being hooked to the hook switch 13. That is, the hook switch 13 detects an instruction to start and end a call from the user.

[0057] In this embodiment, the state where the handset 20 is not hooked on the hook switch 13 is defined as the off-hook state, and the state where the handset 20 is hooked on the hook switch 13 is defined as the on-hook state. However, the present invention is not limited to this. For example, even if the handset 20 is in a state of being hooked on the hook switch 13 when a predetermined key (call instruction detection unit) different from the hook switch 13 is pressed once by the communication terminal 1, it is regarded as the "off-hook state", and it may be configured to enter the "on-hook state" when the predetermined key is pressed again.

[0058] Details will be described later. After the handset 20 enters the off-hook state and the PTT off is detected by the PTT detection unit 74, when the PTT on is detected, the call control unit 71 controls to start a PTT-mode call.

[0059] FIG. 4 is a schematic circuit diagram illustrating the connection relationship between the main body 10 of the communication terminal 1 and the headset 90. In FIG. 4, the left side is the headset 90 side, and the right side is the main body 10 side. In FIG. 4, illustration of matters having a low relationship with the main part of this embodiment is omitted.

[0060] As shown in FIG. 4, the headset side speaker 91 is connected to the external connection terminal 47 of the communication terminal 1 via two speaker side wirings in the headset 90. On the other hand, the headset side microphone 92 is connected to the external connection terminal 47 via two microphone side wirings in the headset 90. That is, the external connection terminal 47 is provided with two terminals corresponding to the two speaker side wirings and two terminals corresponding to the two microphone side wirings.

[0061] And the headset side PTT button 93 is located between the headset side microphone 92 and the external connection terminal 47 in one of the microphone side wirings. Actually, the speaker side connection wiring and the microphone side wiring are connected to the headset side connector, and the headset side connector is connected to the external connection terminal 47 on the main body side.

[0062] In this embodiment, it is assumed that the handset 20 also has the same circuit configuration as the headset 90 in FIG. 4. Therefore, as long as there is no content contradiction, the description of each part of the headset 90 regarding the connection relationship with the main body 10 in FIG. 4 also applies to the corresponding parts of the handset 20.

[0063] The main body 10 in the example of FIG. 4 has a resistor 81 and a switching element 82. As the switching element 82, any transistor can be used. In FIG. 4, a bipolar transistor having a base, an emitter, and a collector is illustrated as the switching element 82.

[0064] The switching element 82 is located between the external connection terminal 47 and the PTT detection unit 74. The base of the switching element 82 is connected to the external connection terminal 47 so as to correspond to the microphone-side wiring in the headset 90. The emitter of the switching element 82 is connected to the voltage terminal 83 of the main body 10. The main body 10 has a power supply (not shown) that applies a DC voltage of a constant value (e.g., 3.3V) to the voltage terminal 83.

[0065] As shown in FIG. 4, the resistor 81 has a ground terminal and a non-ground terminal. The non-ground terminal of the resistor 81 is connected to the collector of the switching element 82. And the non-ground terminal of the resistor 81 is connected to the PTT detection unit 74. Therefore, the PTT detection unit 74 can acquire the voltage of the non-ground terminal of the resistor 81.

[0066] According to the circuit configuration of FIG. 4, the voltage of the non-ground terminal of the resistor 81 can change according to the conduction state of the PTT button 93 on the headset side. Thereby, the PTT detection unit 74 determines the conduction state of the PTT button 93 on the headset side based on the voltage of the non-ground terminal of the resistor 81.

[0067] First, consider the state where the headset-side PTT button 93 is not pressed by the user of the communication terminal 1. That is, consider the case where the headset-side PTT button 93 is in the PTT off state. In this case, the headset-side PTT button 93 in FIG. 4 is in a non-conductive state. From this, no current flows from the external connection terminal 47 to the headset-side microphone 92.

[0068] Therefore, the switching element 82 is in a non-conductive state. Thus, no current flows from the grounded terminal to the non-grounded terminal of the resistor 81. For this reason, the voltage of the non-grounded terminal of the resistor 81 becomes a Low value (0V in the example of FIG. 4).

[0069] From the above, when the voltage of the non-grounded terminal of the resistor 81 is a Low value, the PTT detection unit 74 determines that the headset-side PTT button 93 is in the PTT off state. In other words, when there is no conduction between the two terminals respectively connected to the two microphone-side wirings of the headset-side microphone 92, the PTT detection unit 74 detects that the headset-side PTT button 93 is in the PTT off state.

[0070] After that, consider the case where the headset-side PTT button 93 is pressed by the user. Triggered by the pressing of the headset-side PTT button 93, the headset-side PTT button 93 transitions to the PTT on state. That is, the headset-side PTT button 93 in FIG. 4 transitions to a conductive state.

[0071] As a result, a voltage is supplied from the voltage terminal 83 to the headset-side microphone 92. Therefore, current flows from the voltage terminal 83 to the headset-side microphone 92 via the switching element 82, the external connection terminal 47, and the headset-side PTT button 93.

[0072] As described above, triggered by the transition of the headset-side PTT button 93 to the conductive state, the switching element 82 also transitions to the conductive state. As a result, current flows from the collector of the switching element 82 to the grounded terminal of the resistor 81. For this reason, the voltage of the non-grounded terminal of the resistor 81 becomes a High value.

[0073] In the example of FIG. 4, the High value of the voltage of the non-grounded terminal of resistor 81 is approximately equal to the product of the voltage value of voltage terminal 83 and a predetermined voltage division ratio. The voltage division ratio is determined as a value obtained by dividing the resistance value of resistor 81 by the sum of the resistance values of a plurality of resistors existing on the current path from voltage terminal 83 to the grounded terminal of resistor 81.

[0074] From the above, when the voltage of the non-grounded terminal of resistor 81 is at the High value, PTT detection unit 74 may determine that the headset-side PTT button 93 is in the PTT-on state. In other words, when there is conduction between the two terminals respectively connected to the two microphone-side wirings of headset-side microphone 92, PTT detection unit 74 detects the PTT-on of headset-side PTT button 93.

[0075] As described above, the explanations regarding headset-side microphone 92 and headset-side PTT button 93 in FIG. 4 also apply to handset-side microphone 22 and handset-side PTT button 23. Therefore, in the present embodiment, PTT detection unit 74 detects PTT-on when there is conduction between the two terminals connected to handset-side microphone 22 or headset-side microphone 92, and detects PTT-off when there is no conduction.

[0076] According to PTT detection unit 74, for a microphone in which a PTT button switch is inserted in the connection line of a normal microphone, the PTT-on and PTT-off of the PTT button corresponding to the microphone can be detected. Therefore, in the present embodiment, it is not necessary to provide an individual connection line to detect the operation of the PTT button. As a result, an increase in the device cost can be suppressed on both the microphone side and the communication terminal side.

[0077] The external connection terminal 47 may have any number of pins as long as it can connect the headset-side speaker 91 and the headset-side microphone 92 to the communication terminal 1. In this embodiment, as the external connection terminal 47, an RJ-9 type 4-pin connector (connector) widely used in the connection between a landline telephone and a receiver is employed. Specifically, the external connection terminal 47 in FIG. 4 consists of two pins for the headset-side speaker 91 and two pins for the headset-side microphone 92.

[0078] The two pins for the headset-side speaker 91 in the example of FIG. 4 are the second pin from the top and the third pin from the top in the external connection terminal 47 of FIG. 4. The two pins for the headset-side microphone 92 in the example of FIG. 4 are the first pin from the top and the fourth pin from the top (the lowermost pin) in the external connection terminal 47 of FIG. 4.

[0079] As described above, in this embodiment, a 4-pin type connector widely used in known handsets and headsets can be used as the external connection terminal. Therefore, the headset-side speaker 91 and the headset-side microphone 92 can be connected to the communication terminal 1 using an inexpensive commercially available 4-pin type connector without using special dedicated components. Also from this, according to this embodiment, an increase in device cost can be suppressed.

[0080] 〔Example of Processing by Communication Terminal 1〕 FIG. 5 is a flowchart illustrating the flow of processing by the communication terminal 1. Hereinafter, the flow of processing will be described on the premise of a configuration in which the headset-side PTT button 93 is provided on the headset 90. In step S1, the call control unit 71 determines whether the handset 20 is in the off-hook state based on the pressed state of the hook switch 13.

[0081] If YES in step S1, that is, if the handset 20 is in the off-hook state, the process proceeds to step S2.

[0082] On the other hand, if the answer in step S1 is NO, that is, if the handset 20 is not in the off-hook state, the handset 20 is in the on-hook state, and the process of step S1 is repeated. That is, step S1 corresponds to a process of waiting for the handset 20 to enter the off-hook state.

[0083] In step S2, the PTT detection unit 74 determines whether PTT off is detected. Here, detecting PTT off indicates that the PTT button 93 on the headset side is not pressed. If the answer in step S2 is YES, that is, if PTT off is detected, the process proceeds to step S3. On the other hand, if the answer in step S2 is NO, that is, if the PTT on state continues, step S2 is repeated. That is, step S2 corresponds to a step of waiting to detect that the PTT button 93 on the headset side is not pressed.

[0084] In step S3, the PTT detection unit 74 determines whether the PTT button 93 on the headset side is pressed to turn on PTT. If the answer in step S3 is YES, that is, if the PTT button 93 on the headset side is pressed to turn on PTT, the process proceeds to step S4.

[0085] On the other hand, if the answer in step S3 is NO, that is, if PTT off continues, step S3 is repeated. That is, step S3 corresponds to a step of waiting to detect the turning on of PTT by pressing the PTT button 93 on the headset side.

[0086] In step S4, the call control unit 71 controls to start a PTT-mode call. Thereafter, until the PTT-mode call ends, a speaking operation is performed when PTT is on, and the voice of the call destination is output when PTT is off.

[0087] As described above, generally, in a configuration where the operation of the headset-side PTT button is linked to the switching of the input signal line from the headset-side microphone, when the headset-side PTT button is pressed and the PTT is on, and when a headset is connected such that the input signal line directly from the microphone is connected to the main body of the communication terminal without passing through the PTT button, there will be no difference in the conduction state of the circuit.

[0088] On the other hand, in a communication terminal capable of both IP wireless communication and IP telephone communication, as a headset corresponding to IP wireless communication, both a case where the microphone is connected to the main body of the communication terminal via the PTT button and a case where, as a headset corresponding to IP telephone communication, it is connected without passing through the PTT button are assumed. Therefore, it cannot be determined that the PTT button has been pressed just because there is conduction in the input signal line from the microphone.

[0089] In contrast, the call control unit 71 in the present embodiment performs control to start a PTT-based call when PTT on is detected after PTT off has been detected once. Therefore, the communication terminal 1 can appropriately start a PTT-based call.

[0090] 〔Example of Realization by Software〕 The functions of the communication system 100 (hereinafter, referred to as the "device" for convenience) can be realized by a program for causing a computer to function as the device, and by a program for causing a computer to function as each control block of the device (particularly, each part included in the control unit 70).

[0091] In this case, the above device includes a computer having at least one control device (for example, a processor) and at least one storage device (for example, a memory) as hardware for executing the above program. By executing the above program with this control device and storage device, each function described in the above embodiments is realized.

[0092] The above program may be recorded on one or more computer-readable recording media, rather than temporarily. This recording medium may or may not be provided in the above device. In the latter case, the above program may be supplied to the above device via any wired or wireless transmission medium.

[0093] Also, part or all of the functions of each of the above control blocks can also be realized by a logic circuit. For example, an integrated circuit in which a logic circuit functioning as each of the above control blocks is formed is also included in the scope of the present invention.

[0094] 〔Summary〕 The present invention can also be expressed as follows.

[0095] A communication terminal according to aspect 1 of the present invention includes a PTT call processing unit that performs a PTT call by the PTT method, a call control unit that controls the call by the PTT call processing unit, an external connection terminal to which an external connection speaker and an external connection microphone are connected, a PTT detection unit that detects PTT on and PTT off by a PTT button connected via the external connection terminal, and a call instruction detection unit that detects a call start instruction and an end instruction from a user. The call control unit performs control to start the PTT call associated with the detection of PTT on by the PTT detection unit after the PTT off is detected by the PTT detection unit after the call instruction detection unit detects the start instruction.

[0096] According to the above configuration, since the PTT call is started when PTT on is detected after PTT off is detected once, the PTT call can be appropriately started.

[0097] Note that the communication terminal further includes a handset having a handset-side speaker and a handset-side microphone, and the call control unit may perform control to start the PTT call associated with the detection of PTT on by the PTT detection unit after the PTT off is detected by the PTT detection unit after the handset is off-hooked.

[0098] Also, in the communication terminal according to Embodiment 2 of the present invention, in Embodiment 1, the PTT call processing unit makes the PTT call via an IP network.

[0099] According to the above configuration, a PTT call can be made via an IP network such as a LAN or the Internet.

[0100] Further, the communication terminal according to Embodiment 3 of the present invention, in Embodiment 1 or 2, further includes an IP phone processing unit that performs IP phone communication by SIP via an IP network, and the call control unit controls the call by the PTT call processing unit and the call by the IP phone processing unit.

[0101] According to the above configuration, in a communication terminal capable of both IP phone calls and PTT calls, a PTT call can be appropriately started.

[0102] Also, in the communication terminal according to Embodiment 4 of the present invention, in any one of Embodiments 1 to 3, the PTT detection unit detects PTT on when there is conduction between two terminals at the external connection terminal, which are respectively connected to two microphone-side wirings of the external connection microphone, and detects PTT off when there is no conduction.

[0103] According to the above configuration, in a microphone configured by inserting a PTT button switch into a connection line of a normal microphone, PTT on and PTT off by the PTT button can be detected. Therefore, since there is no need to separately provide a connection line to detect the operation of the PTT button, an increase in device cost can be suppressed on both the microphone side and the communication terminal side.

[0104] Further, the communication terminal according to Embodiment 5 of the present invention, in Embodiment 4, the external connection terminal is a connection terminal including two pins for the external connection speaker and two pins for the external connection microphone.

[0105] According to the above configuration, a 4-pin type connector widely used in handsets, headsets, etc. can be connected to the external connection terminal for use. Therefore, various existing products that are inexpensive can be connected and used without using a special voice input device.

[0106] A control method for a communication terminal according to Embodiment 6 of the present invention includes a PTT call processing unit that performs a PTT call by the PTT method, a handset including a handset side speaker and a handset side microphone, an external connection terminal to which an external connection speaker and an external connection microphone are connected, a PTT button connected via the external connection terminal, and a PTT detection unit that detects PTT on and PTT off by at least one of the PTT buttons provided on the handset, and is a control method for a communication terminal, wherein after the handset is in an off-hook state and the PTT off is detected by the PTT detection unit, control is performed to start the PTT call associated with the detection of PTT on by the PTT detection unit.

[0107] According to the above method, the same effect as that of Embodiment 1 described above is achieved.

[0108] 〔Supplementary Notes〕 The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

Explanation of Signs

[0109] 1 Communication terminal 10 Main body 70 Control unit 11 Main body side speaker 12 Main body side microphone 13 Hook switch (call instruction detection unit) 14 PTT button 20 Handset 21 Handset side speaker (external connection speaker) 22 Handset-side microphone (external connection microphone) 23 Handset-side PTT button 47·48 External connection terminals 71 Call control unit 72 IP wireless processing unit (PTT call processing unit) 73 IP phone processing unit 74 PTT detection unit 90 Headset 91 Headset-side speaker (external connection speaker) 92 Headset-side microphone (external connection microphone) 93 Headset-side PTT button

Claims

1. A PTT call processing unit that performs a PTT call by the PTT (Push to Talk) method, A call control unit that controls the call by the PTT call processing unit, An external connection terminal for connecting an external connection speaker and an external connection microphone, A PTT detection unit that detects PTT on and PTT off by a PTT button connected via the external connection terminal, A call instruction detection unit that detects a call start instruction and an end instruction from a user, Comprising, The call control unit performs control to start the PTT call associated with the detection of PTT on by the PTT detection unit after the PTT off is detected by the PTT detection unit after the call instruction detection unit detects the start instruction. A communication terminal.

2. The PTT call processing unit performs the PTT call via an IP (Internet Protocol) network. The communication terminal according to claim 1.

3. Further comprising an IP telephone processing unit that performs IP telephone communication by SIP (Session Initiation Protocol) via an IP (Internet Protocol) network, The call control unit controls the call by the PTT call processing unit and the call by the IP telephone processing unit. The communication terminal according to claim 1.

4. The PTT detection unit detects PTT on when there is conduction between two terminals in the external connection terminal, which are respectively connected to two microphone-side wirings of the external connection microphone, and detects PTT off when there is no conduction. The communication terminal according to claim 1.

5. The external connection terminal is a connection terminal composed of two pins for the external connection speaker and two pins for the external connection microphone. The communication terminal according to claim 4.

6. A control method for a communication terminal, comprising: a PTT call processing unit that performs a PTT call by the PTT method, an external connection terminal for connecting an external connection speaker and an external connection microphone, and a PTT detection unit that detects PTT on and PTT off by a PTT button connected via the external connection terminal, and a call instruction detection unit that detects a call start instruction and an end instruction from a user. After the call instruction detection unit detects the start instruction and the PTT off is detected by the PTT detection unit, control is performed to start the PTT call associated with the detection of PTT on by the PTT detection unit. A control method for a communication terminal. A control method for a communication terminal, which performs control to start the PTT call associated with the detection of PTT on by the PTT detection unit after the PTT off is detected by the PTT detection unit after the call instruction detection unit detects the start instruction.

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