IP terminal equipment

Abstract

To perform appropriately PoE power feeding regardless of which LAN port a PoE power feeding device is connected to, regarding an IP terminal device having a plurality of LAN ports.SOLUTION: Power supply lines of ports PT1 and PT2 are connected to power supply circuit 107 via relay circuit 103 . A relay circuit 103 is switched and controlled by a power supply switching circuit 104 according to the state of each power supply line. The power supply switching circuit 104 (1) connects the power supply line of a predetermined power supply port to a power supply circuit 107 when the power supply voltage is not supplied from either of the ports PT1 and PT2. (2) When a power supply voltage is supplied from one LAN port of the ports PT1 and PT2, the power supply line of the one LAN port is connected to the power supply circuit 107. (3) When power supply voltage is supplied from both ports PT1 and PT2, the previous connection state is maintained.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an IP terminal device having a PoE (Power over Ethernet) function that can receive power supply via a LAN cable, such as an IP (Internet Protocol) telephone, an IP camera door phone, or the like. [Background technology]

[0002] As disclosed in Patent Document 1 described later, for example, some IP telephones are provided with two LAN ports on the assumption that the IP telephone and a PC (Personal Computer) will be used by the same person at a desk in an office, etc. In this case, of the two LAN ports provided on the IP telephone, one LAN port is used to connect the device itself (the IP telephone) to the network, and the other LAN port is used to connect a PC. Therefore, the PC can be connected to the network via the IP telephone.

[0003] This prevents the hub devices in the office from running out of power and the LAN cable wiring from becoming tangled. Also, if the IP phone has a PoE function, it can be powered through the LAN cable. This means that there is no need to have a commercial power outlet near the IP phone, which improves the freedom of placement of the IP phone. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-37890 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of an IP phone with two LAN ports as described above, one LAN port is intended for connection to a PC that receives power from an external commercial power source, so the LAN port provided for the PC does not need to be a LAN port that supports PoE power supply. For this reason, in many cases, an IP phone with two LAN ports has only one LAN port that supports PoE power supply. In other words, of the two LAN ports, one is a port that supports PoE power supply and is used for connecting to a network (for NW) that can connect to a power supply hub, and the other is a port that does not support PoE power supply and is used for connecting to a PC (for PC).

[0006] In this case, because the two LAN ports on the IP phone look almost identical, it is possible that the installer will make a mistake when connecting them. Also, in terms of the layout of the equipment, it may be better to connect the PC to the LAN port for the network that supports PoE power supply, and connect the network to the LAN port for the PC that does not support PoE power supply. However, if this is not possible, problems will arise such as the wiring of the LAN cables becoming disorganized and messy. This type of problem can occur not only with IP phones, but also with various IP terminal devices that have two or more LAN ports.

[0007] In view of the above, an object of the present invention is to provide an IP terminal device having a plurality of LAN ports that can perform appropriate PoE power supply regardless of which LAN port a PoE power supply device is connected to. [Means for solving the problem]

[0008] In order to solve the above problem, the IP terminal device of the invention described in claim 1 comprises: a power supply circuit that receives an input power supply voltage and generates an output power supply voltage to be supplied to each unit; 2 or more LAN (Local Area Network) ports, a relay circuit to which the power supply lines of the two or more LAN ports are connected and which switches which of the LAN ports' power supply lines is connected to the power supply circuit; a power supply switching circuit to which the power supply lines of the two or more LAN ports are connected and which controls switching of the relay circuit based on a state of a power supply voltage applied through the power supply lines of the two or more LAN ports; Equipped with The power supply switching circuit includes: If there is no power supply voltage from any of the two or more LAN ports, 、 Connecting the power line of a specific LAN port to the power circuit; Do not connect the power lines of other LAN ports to the power circuit. When a power supply voltage is supplied from one of the two or more LAN ports, the power supply line of the one LAN port is connected to the power supply circuit; Do not connect the power lines of other LAN ports to the power circuit. If the power supply voltage is supplied from more than one of the two or more LAN ports, By maintaining the connection of the power line of the LAN port that was previously receiving power to the power circuit and maintaining the power lines of the other LAN ports unconnected to the power circuit, The relay circuit is controlled so as to maintain the previous connection state. It is characterized by:

[0009] According to the IP terminal device of the invention described in claim 1, the power lines from each of the two or more LAN ports are connected to the power circuit via the relay circuit. The relay circuit is switched by a power supply switching circuit to which the power lines from each of the two or more LAN ports are connected, depending on the state of each power supply line. Specifically, the power supply switching circuit controls the switching of the relay circuit as shown in the following (1) to (3).

[0010] (1) If there is no power supply voltage from any of the two or more LAN ports, connect the power line of the specified power port to the power circuit. Do not connect the power lines of other LAN ports to the power circuit. (2) When power voltage is supplied from one of two or more LAN ports, the power line of that LAN port is connected to the power circuit. Do not connect the power lines of other LAN ports to the power circuit.(3) When the power supply voltage is supplied from two or more of the LAN ports, the relay circuit is controlled. The power supply line of the LAN port that was previously receiving power is maintained connected to the power supply circuit, and the power supply lines of the other LAN ports are maintained unconnected to the power supply circuit. Controls the relay circuit. Effect of the Invention

[0011] According to this invention, in an IP terminal device equipped with multiple LAN ports, PoE power supply can be performed appropriately regardless of which LAN port the LAN cable is connected to. Therefore, there is no risk of incorrectly inserting the LAN cable, and the LAN cable can be flexibly connected according to the installation location of the IP terminal device and the installation locations of other electronic devices connected to the IP terminal device. [Brief description of the drawings]

[0012] [Figure 1] 1 is a block diagram for explaining a configuration example of an IP telephone system according to an embodiment; [Diagram 2] 1A and 1B are diagrams for explaining a power supply hub according to an embodiment. [Diagram 3] FIG. 1 is a block diagram for explaining an IP telephone set according to an embodiment. [Figure 4] 2 is a block diagram for explaining a PoE power supply unit of the IP telephone according to the embodiment. FIG. [Diagram 5] 1 is a diagram for explaining a power supply switching circuit of a PoE power supply unit of an IP telephone according to an embodiment. [Figure 6] 1 is a diagram illustrating an operation truth table of a power supply switching circuit of a PoE power supply unit of an IP telephone according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of an IP terminal device of the present invention will be described with reference to the drawings. The IP terminal device of the present invention can be applied to various electronic devices that communicate using IP (Internet Protocol), such as an IP telephone, an IP camera door phone, a Web camera, and a wireless LAN access point. However, in the following, in order to simplify the explanation, the IP terminal device of the present invention will be described as being applied to an IP telephone.

[0014] [Example of IP telephone system configuration] FIG. 1 is a block diagram for explaining an example of the configuration of an IP telephone system. The IP telephone system is configured using IP telephones to which the IP terminal device according to the present invention is applied. As shown in FIG. 1, a main unit 2 is connected to a network 1, and a power supply hub 3 is connected to the main unit 2. IP telephones 4(1), 4(2), ..., 4(n) are connected to the power supply hub 3, and corresponding PCs 5(1), 5(2), ..., 5(n) are connected to the IP telephones 4(1), 4(2), ..., 4(n). The letter n in parentheses usually means an integer of 1 or more. However, since IP telephones 4(1), 4(2) and PCs 5(1), 5(2) already exist, in FIG. 1, it means an integer of 3 or more.

[0015] <Outline of Network 1 and Main Unit 2> Although not shown, the network 1 includes various wide area communication networks such as a public switched telephone network (analog line network), an Integrated Services Digital Network (ISDN), an IP telephone network, and the Internet. The main unit 2 has a Unified Threat Management (UTM) function, a Session Initiation Protocol (SIP) server function, and a Private Branch eXchange (PBX) function. This allows a user to connect to the Internet through the main unit 2 and browse web pages on the Internet, download and upload data, and send and receive e-mail. In addition, the main unit 2 can be used to make and receive calls using an IP telephone network. In addition, the main unit 2 can be used to make and receive calls using a public switched telephone network or ISDN.

[0016] The UTM function provides efficient and comprehensive protection for computer networks against threats such as computer viruses and hacking. The SIP server function manages and controls IP telephone systems that use SIP, managing data that associates user identification information such as telephone numbers with location information on the network such as IP addresses, and controls calls. The PBX function functions as a telephone exchange that connects a large number of private telephone sets to the public switched telephone network or ISDN.

[0017] <Outline of Power Supply Hub 3> FIG. 2 is a diagram for explaining the power supply hub 3. The power supply hub 3 is a so-called PoE power supply device that has multiple LAN ports (power supply ports) and can not only connect networks, but also receive commercial power and supply power (supply electricity) to an IP phone connected to the hub itself. The power supply hub 3 has multiple power supply ports. However, for ease of explanation, FIG. 2(A) shows a portion including one subsequent stage device side port (power supply port) 302 and its corresponding preceding stage device side port 301. The LAN cable connecting the devices is configured with four twisted pair wires, with eight insulated coated conductors numbered 1 to 8 twisted together in pairs. Specifically, the twisted pair wires are configured with pairs of wires, such as 1 and 2, 3 and 6, 4 and 5, and 7 and 8.

[0018] There are two types of PoE technology (power supply technology) that transmits and receives data and supplies power voltage through such LAN cables: Alternative A and Alternative B. In either case, as shown in Figure 2(B), twisted pair wires 1 and 2 and twisted pair wires 3 and 6 are used for data communication. In the case of the Alternative A method, as shown in Figure 2(B), power voltage is supplied by superimposing the power voltage on the twisted pair wires 1 and 2 and twisted pair wires 3 and 6 used for data communication. Therefore, in the case of the Alternative A method, twisted pair wires 4 and 5 and twisted pair wires 7 and 8 are open (free). In contrast, in the case of Alternative B, as shown in Figure 2(B), power is supplied through twisted pair wires numbered 4 and 5 and twisted pen wires numbered 7 and 8, which are separate from those used for data communication. Therefore, in the case of Alternative B, there are no open (vacant) twisted pair wires.

[0019] The power supply hub 3 may adopt either the alternative A system or the alternative B system. However, in this embodiment, for the sake of simplicity, the following IP telephones 4(1), 4(2), ..., 4(n) adopt the alternative A system. Therefore, in this embodiment, the power supply hub 3 and the IP telephones 4(1), 4(2), ..., 4(n) are also connected using the alternative A system. As shown in FIG. 2(A), the power supply hub 3 includes a front-stage device port 301 and a rear-stage device port 302 as ports (connection ends) to which a LAN cable is connected. In the front-stage device port 301 and the rear-stage device port 302, the eight terminals indicated by circles with numbers correspond to the eight insulated conductors of the LAN cable, numbered 1 to 8. Therefore, data communication is carried out using twisted pair wires #1 and #2 as the transmission line (TX) and twisted pair wires #3 and #6 as the reception line (RX).

[0020] 2A, for example, a power supply voltage of 48V (volts) formed based on a commercial power supply from an AC outlet is applied to the No. 1 and No. 2 twisted pair wires and the No. 3 and No. 6 twisted pair wires of the downstream device side port 302. This makes it possible to superimpose the power supply voltage on the communication data being transmitted and received and supply the power supply voltage to the downstream device connected to the downstream device side port 302. That is, the downstream device side port 302 of the power supply hub 3 functions as a power supply port. In this way, in the upstream device side port 301 and the downstream device side port 302 of the power supply hub 3, the pair of terminals No. 1 and No. 2 and the pair of terminals No. 3 and No. 6 are used as data communication terminals. Furthermore, in the downstream device side port 302, the pair of terminals No. 1 and No. 2 and the pair of terminals No. 3 and No. 6 are also used as power supply terminals for the power supply voltage.

[0021] That is, the power supply hub 3 relays data communication between the main device 2 connected to the front-stage device-side port 301 and, for example, an IP telephone 4(1) or the like connected to the rear-stage device-side port 302. Further, the power supply hub 3 supplies a power voltage to a rear-stage device connected to the rear-stage device-side port 302 that functions as a power supply port.

[0022] <Overview of IP telephone 4> Each of the IP telephones 4(1), 4(2), …, 4(n) is connected to the network 1 through the power supply hub 3 and the main device 2, and realizes the function of making a call to a target counterpart, receiving an incoming call, connecting a call line, and making a call. Since each of the IP telephones 4(1), 4(2), …, 4(n) is similarly configured, hereinafter, unless otherwise particularly distinguished, the IP telephones 4(1), 4(2), …, 4(n) are collectively referred to as the IP telephone 4.

[0023] FIG. 3 is a block diagram for explaining the IP telephone 4. As shown in FIG. 3, the IP telephone 4 includes LAN ports PT1, PT2, a LAN interface unit 401, a packet transceiver unit 402, a voice codec 403, a handset 404, and a control unit 410. The handset 404 is a so-called transceiver including a receiver (speaker) 4041 and a transmitter (microphone) 4042.

[0024] As described above, the LAN ports PT1, PT2 correspond to the LAN interface of the alternative A method. Therefore, the LAN ports PT1, PT2 correspond to the rear-stage device-side port 302 of the power supply hub 3 described with reference to FIG. 2, and can perform data communication and receive power supply using the first and second twisted pair wires and the third and sixth twisted pair wires. Hereinafter, the LAN ports PT1 and PT2 are simply described as the ports PT1 and PT2.

[0025] In the IP telephone 4 of this embodiment, as a rough guide, port PT1 is for connecting to a PC (Personal Computer), and port PT2 is for connecting to a NW (Network), and in the default state, power is supplied through port PT2. However, as described above, both ports PT1 and PT2 can function not only for data communication but also as power supply ports that can receive power. For this reason, as will be described in detail later, even if a LAN cable from the power supply hub 3 is connected to port PT1 and a LAN cable from a PC is connected to port PT2, power can be properly supplied. Of course, data communication can also be performed properly.

[0026] The LAN interface unit 401 includes a PoE power supply unit 4011 and a packet processing unit 4012. The PoE power supply unit 4011 receives power via port PT1 or port PT2, forms a driving power supply to be supplied to each unit of the IP telephone 4, and performs processing to supply this to each unit. The PoE power supply unit 4011 will be described in detail later. The packet processing unit 4012 performs processing to allocate the destinations of packets to be received and transmitted.

[0027] That is, the packet processing unit 4012 analyzes a packet received through port PT1, and if it determines from the source identification information etc. that the received packet is a packet from a PC, it sends the packet to the network side through port PT2. Also, in this case, the packet processing unit 4012 analyzes a packet received through port PT2, and if it determines from the destination identification information etc. that the received packet is a packet addressed to a PC, it sends the packet to the PC through port PT1.

[0028] Similarly, the packet processing unit 4012 analyzes a packet received through port PT2, and if it determines from the source identification information etc. that the received packet is a packet from a PC, it sends the packet to the network side through port PT1. Also, in this case, the packet processing unit 4012 analyzes a packet received through port PT1, and if it determines from the destination identification information etc. that the received packet is a packet addressed to a PC, it sends the packet to the PC through port PT2.

[0029] Furthermore, the packet processing unit 4012 analyzes a packet received through port PT1 or port PT2, and if the packet contains control data or voice data for a call, supplies the packet to the downstream packet transmission / reception unit 402. Furthermore, the packet processing unit 4012 sends packets from the packet transmission / reception unit 402 to the network side through port PT1 or port PT2. For this reason, the packet processing unit 4012 knows whether or not a device is connected to each of port PT1 and port PT2, and if a device is connected, what kind of device is connected. This allows packets containing control data or voice data for a call to be sent to the network side.

[0030] When the packet transmitting / receiving unit 402 receives a packet from the packet processing unit 4012 of the LAN interface unit 401, it disassembles the packet and extracts control data and audio data. The packet transmitting / receiving unit 402 supplies the extracted control data to the control unit 410, and supplies the extracted audio data to the audio codec 403. As a result, when the control data indicates an incoming call to the device itself, it can notify the user of the incoming call by controlling a ringer (not shown) to emit an incoming call tone or by blinking a specified LED (Light Emitting Diode).

[0031] When a predetermined off-hook operation, such as picking up handset 404, is performed in response to the incoming call notification, this is detected by control unit 410. In this case, under the control of control unit 410, a transmission packet including control data indicating that an off-hook operation has been performed is formed in packet transceiver unit 402 and sent to the network side via packet processing unit 4012 and port PT1 or port PT2. This allows the call line to be connected in response to the incoming call, enabling a call to be made.

[0032] That is, the voice codec 403 converts the voice data from the packet transmitting / receiving unit 402 into an analog voice signal, and supplies this to the speaker 4041 of the handset 404. As a result, the speaker 4041 of the handset 404 emits a voice corresponding to the received voice data. The voice codec 403 also converts an analog voice signal collected through the microphone 4042 of the handset 404 into digital voice data, and supplies this to the packet transmitting / receiving unit 402. The packet transmitting / receiving unit 402 forms a transmission packet from the voice data from the voice codec 403 and the control data from the control unit 410. The transmission packet is sent to the network side through the packet processing unit 4012 of the LAN interface unit 401 and also through the port PT1 or port PT2. In this way, an incoming call can be answered and a conversation can be made.

[0033] Furthermore, when making a call from the IP telephone 4, an off-hook operation is performed, and then a call is made by inputting the telephone number of the other party through the operation unit 411 connected to the control unit 410. In this case, under the control of the control unit 410, the packet transmitting / receiving unit 402 forms a packet requesting a call and sends it to the network side through the packet processing unit 4012 and port PT1 or port PT2, thereby making it possible to make a call to the other party.

[0034] After that, if the other party responds, as described above, the voice data from the other party is supplied from port PT1 or port PT2 via the packet processing unit 4012 to the packet transceiver 402 and packet-decomposed. The voice data obtained by the packet decomposition is supplied to the voice codec 403, converted into an analog voice signal, supplied to the speaker 4041, and the voice is emitted from the speaker 4041 to the other party. Also, the voice signal picked up through the microphone 4042 is converted into digital voice data by the voice codec 403 and packetized by the packet transceiver 402. The packetized voice data is sent out to the network side via the packet processing unit 4012 through port PT1 or port PT2 and transmitted to the other party.

[0035] In this way, the IP phone 4 can perform call control by the control unit 410, receive incoming calls, make outgoing calls, connect a call line, and conduct a call. Also, when a PC is connected to port PT1 or port PT2, the IP phone 4 functions as a repeater and can connect the PC to the network 1. Furthermore, the IP phone 4 of this embodiment is configured to be able to receive power appropriately regardless of whether the power supply hub 3 is connected to port PT1 or port PT2. That is, the power supply hub 3 can be connected to either port PT1 or port PT2, and the PC5 can be connected to either port PT1 or port PT2. To realize this function, a PoE power supply unit 4011 is provided.

[0036] <Overview of PC5> Each of PC5(1), PC5(2),..., PC(n) is a commercially available PC, and as long as it has a LAN port, it can be of various types such as a desktop PC, a notebook PC, or a tablet PC. Also, in this embodiment, there is no particular feature in the configuration of the PC, and a commercially available one can be directly connected. Since the configuration of the PC is also well-known, the description of the configuration example of PC5 is omitted in this specification.

[0037] [Configuration example of PoE power supply unit 4011 of IP telephone 4] Fig. 4 is a block diagram for explaining a configuration example of the PoE power supply unit 4011 of the IP telephone 4. As shown in Fig. 4, the twisted pair wires No. 1 and No. 2 and the twisted pair wires No. 3 and No. 6 of the port PT1 are connected to a diode bridge 101a. Similarly, the twisted pair wires No. 1 and No. 2 and the twisted pair wires No. 3 and No. 6 of the port PT2 are connected to a diode bridge 101b. Each of the diode bridges 101a and 101b is a combination of four rectifier diodes and has the function of converting AC voltage into DC voltage.

[0038] The positive end of the diode bridge 101a is connected to the input end a of the relay circuit 103a, and the negative end of the diode bridge 101a is connected to the input end d of the relay circuit 103b. The positive end of the diode bridge 101b is connected to the input end b of the relay circuit 103a, and the negative end of the diode bridge 101b is connected to the input end e of the relay circuit 103b. The output end c of the relay circuit 103a is connected to the class discrimination circuit / power supply circuit 107, and the output end f of the relay circuit 103b is connected to the class discrimination circuit / power supply circuit 107.

[0039] That is, the power supply voltage (AC voltage) applied to port PT1 is converted to a DC voltage by the diode bridge 101a, and then applied to the class discrimination circuit / power supply circuit 107 via the relay circuits 103a and 103b. Similarly, the power supply voltage (AC voltage) applied to port PT2 is converted to a DC voltage by the diode bridge 101b, and then applied to the class discrimination circuit / power supply circuit 107 via the relay circuits 103a and 103b. In this case, the relay circuits 103a and 103b are switched by the power supply switching circuit 104, and the voltage applied to the class discrimination circuit / power supply circuit 107 is switched between the power supply voltage from port PT1 and the power supply voltage from port PT2.

[0040] For this reason, the power supply voltage rectified by the diode bridge 101a is supplied to the power supply switching circuit 104 via the photocoupler 102a, and the power supply voltage rectified by the diode bridge 101b is supplied to the power supply switching circuit 104 via the photocoupler 102b. The power supply switching circuit 104, which will be described in detail later, controls the switching of the relay circuits 103a and 103b based on the power supply state from the port PT1 and the power supply state from the port PT2. An example configuration and operation of the power supply switching circuit 104 will be described in detail later.

[0041] The photocouplers 102a and 102b are, for example, composed of a light-emitting diode and a phototransistor, and convert an electric signal into light inside and then back into an electric signal, thereby transmitting the signal while being electrically insulated. Therefore, the signal system having the port PT1 as an input end and the signal system having the port PT2 as an input end are insulated by the relay circuits 103a and 103b and the photocouplers 102a and 102b. As a result, even if a surge current occurs in the signal system having the port PT1 as an input end, it does not affect the signal system having the port PT2 as an input end. Conversely, even if a surge current occurs in the signal system having the port PT2 as an input end, it does not affect the signal system having the port PT1 as an input end. The surge current is a "big wave current" that occurs in an electric circuit that exceeds the steady state instantaneously, and can be generated by various factors such as opening and closing a switch or a lightning strike.

[0042] In addition, in FIG. 4, the relay circuit 103a and the relay circuit 103b are shown as separate entities, but as shown by the dotted line connection, the relay circuit 103a and the relay circuit 103b operate in conjunction with each other. More specifically, the relay circuit 103a and the relay circuit 103b can be configured as a non-latching type that operates only while a signal is being input, and a double pole double throw (DPDT (Double Poles Double Throws) type). Here, the pole (Pole) means the number of circuits that the switch can control simultaneously, and the throw (Throw) means the number of connection paths on the circuit that the switch can control. Therefore, the relay circuit 103a and the relay circuit 103b constitute one relay circuit (switch circuit) 103. In this case, the relay circuit 103 can simultaneously control the diode bridge 101a and the diode bridge 101b, and the number of connection paths on the circuit that can be controlled is two, so it is a non-latching DPDT type.

[0043] The charging circuit 105 and the large-capacity capacitor 106 supply driving power to the power supply switching circuit 104 even when no power is supplied through the ports PT1 and PT2, thereby enabling the relay circuits 103a and 103b to be appropriately switched. That is, the charging circuit 105 and the large-capacity capacitor 106 constitute a driving circuit that supplies driving power to the power supply switching circuit 104 and the relay circuits 103a and 103b. The large-capacity capacitor 106 is realized by, for example, an electric double layer capacitor. Also, it is assumed that the large-capacity capacitor 106 has been naturally discharged due to a long period of unused time (several months to several years or more). Even in this case, when power is supplied through the port PT1 or port PT2, it can be charged by the charging circuit 105 by receiving power through the class discrimination circuit / power supply circuit 107 described later.

[0044] Also, general PoE-compatible terminals such as IP telephones may be adapted to support power supply from an AC adapter so that they can be connected to non-PoE hub devices that do not have a power supply function. In this case, as shown in FIG. 4, a circuit configuration is provided in which the large-capacity capacitor 106 can be charged through the charging circuit 105 even when power is supplied from the AC adapter. This makes it possible to charge the large-capacity capacitor 106 even when the power supply hub 3 is not connected to the port PT1 or port PT2. Therefore, the large-capacity capacitor 106 can be charged with power from the AC adapter as necessary, and the power supply switching circuit 104 can be appropriately operated to control the switching of the relay circuits 103a and 103b.

[0045] The class discrimination circuit / power supply circuit 107 discriminates the power consumption class of the subsequent circuit unit by applying two different voltages in the range of 2.8 to 10V (volts) to the subsequent circuit unit and measuring the current. For example, if the detected current is 0 to 5mA (milliamperes), it discriminates that the power consumption is Class 0, which is 0.44 to 12.95W (watts), and if the detected current is 8 to 13mA, it discriminates that the power consumption is Class 1, which is 0.44 to 3.84W. If the detected current is 16 to 21mA (milliamperes), it discriminates that the power consumption is Class 2, which is 3.84 to 6.49W, and if the detected current is 25 to 31mA, it discriminates that the power consumption is Class 3, which is 6.49 to 12.95W. The class discrimination circuit / power supply circuit 107 forms a power supply voltage to be supplied to the downstream circuit section from the power supply voltage supplied through port PT1 or port PT2 depending on the power consumption class of the downstream circuit section that has been discriminated, and applies (supplies) this to the circuit section within the IP telephone 4.

[0046] In this way, the PoE power supply unit 4011 can appropriately grasp the power supply state through port PT1 or port PT2 and appropriately switch the relay circuits 103a, 103b, thereby appropriately applying the power supply voltage to the class discrimination circuit / power supply circuit 107. As a result, regardless of whether power is supplied through port PT1 or port PT2, the power supply voltage can be applied to the class discrimination circuit / power supply circuit 107, and a power supply voltage can be formed and applied (supplied) to the subsequent circuit unit. In this case, the power supply switching circuit 104 is responsible for the function of appropriately switching the relay circuits 103a, 103b. The power supply switching circuit 104 will be described in detail below.

[0047] <Configuration example and operation of power supply switching circuit 104> FIG. 5 is a diagram for explaining a configuration example of the power supply switching circuit 104 of the PoE power supply unit 4011 of the IP telephone 4. FIG. 6 is a diagram showing an operation truth table of the power supply switching circuit 104 of the PoE power supply unit 4011 of the IP telephone 4. In FIG. 5, the power supply switching circuit 104 is a part surrounded by a dotted line. However, for the sake of simplicity, the front part of the PoE power supply unit 4011 (part consisting of ports PT1 and PT2, diode bridges 101a and 101b, and photocouplers 102a and 102b) and the relay circuit 103 are also shown. Note that while two relay circuits 103a and 103b are shown in FIG. 4, one relay circuit 103 of a double-pole double-throw type (DPDT type) is shown in FIG. 5. That is, the relay circuit 103 corresponds to the two relay circuits 103a and 103b in FIG. 4.

[0048] 5, the power supply switching circuit 104 includes an XOR (exclusive OR) circuit 1041, a NOT (negative logic) circuit 1042, a NOR (negative OR) circuit 1043, an AND (logical AND) circuit 1044, and a state holding circuit 1045. A power supply voltage supplied through a port PT1 is applied to the power supply switching circuit 104 via a diode bridge 101a and a photocoupler 102a. An input signal in1 corresponding to the power supply voltage applied through the photocoupler 102a is supplied to the XOR circuit 1041, the NOT circuit 1042, and the NOR circuit 1043, as shown in FIG.

[0049] Similarly, the power supply voltage supplied through the port PT2 is applied to the power supply switching circuit 104 via the diode bridge 101b and the photocoupler 102b. An input signal in2 according to the power supply voltage applied through the photocoupler 102b is supplied to an XOR circuit 1041, a NOT circuit 1042, and a NOR circuit 1043, as shown in FIG. 5. An output signal from the XOR circuit 1041 and an output signal from the NOT circuit 1042 are supplied to an AND circuit 1044. An output signal from the AND circuit 1044 and an output signal from the NOR circuit 1043 are supplied to a state holding circuit 1045. The state holding circuit 1045 forms an output signal out for switching the relay circuit 103 from the signal supplied thereto, and uses this to control the switching of the relay circuit 103.

[0050] The XOR circuit 1041 performs a logical operation in which the output is "0" when both input terminals are "1" or when both are "0", and the output is "1" when one input is "1" and the other is "0". The NOT circuit 1042 performs a logical operation in which the output is inverted with respect to the input. The NOR circuit 1043 performs a logical operation in which the output is "1" only when all input terminals are "0". The AND circuit 1044 performs a logical operation in which the output is "1" only when all input terminals are "1". The state holding circuit 1045 has a function of controlling the relay circuit 103 to hold the state of the relay circuit 103 when PoE devices are connected to both port PT1 and port PT2 and power is being supplied from both.

[0051] In FIG. 5, the photocouplers 102a and 102b and the circuit portion constituting the power supply switching circuit 104 indicate the states of the input and output signals, for example, "0011" and "1010". The operation truth table in FIG. 6 shows all of these operation states. As shown in FIG. 6, for each of the ports PT1 and PT2, when a PoE power supply device such as the power supply hub 3 is connected and power is being supplied, the state is "1 (high)", and when the PoE power supply device is not connected and power is not being supplied, the state is "0 (low)". In this case, the LAN port state can be divided into cases as shown in the two left columns in FIG. 6. That is, there are four cases: both ports PT1 and PT2 are not connected (first row), port PT1 is not connected and port PT2 is connected (second row), port PT1 is connected and port PT2 is not connected (third row), and both ports PT1 and PT2 are connected (fourth row).

[0052] According to the operational truth table of Fig. 6, "0011" shown in the first column of Fig. 6 and shown to the left of the photocoupler 102a in Fig. 5 is a possible state of the signal applied to the light-emitting diode of the photocoupler 102a. The output signal of the photocoupler 102a is an inverted signal of the input signal. Therefore, the possible states of the output signal of the photocoupler 102a, i.e., the input signal in1 input from the phototransistor of the photocoupler 102a to the power supply switching circuit 104, are "1100", as shown to the right of the photocoupler 102a in Fig. 5 and in the third column of Fig. 6.

[0053] Also, "0101" shown in the second column of Fig. 6 and shown to the left of photocoupler 102b in Fig. 5 is a possible state of the signal applied to the light-emitting diode of the photocoupler. The output signal of photocoupler 102b is an inverted signal of the input signal. Therefore, the possible states of the output signal of photocoupler 102b, i.e., the input signal in2 input from the phototransistor of photocoupler 102b to power supply switching circuit 104, are "1010" as shown to the right of photocoupler 102b in Fig. 5 and in the fourth column of Fig. 6.

[0054] When such input signals in1 and in2 are supplied to the power supply switching circuit 104, the XOR circuit 1041, the NOT circuit 1042, the NOR circuit 1043, the AND circuit 1044, and the state holding circuit 1045 function to generate an output signal out. The output signal output from the state holding circuit 1045 is shown in the fifth column of FIG. 6. That is, when the ports PT1 and PT2 are both unconnected, the input signals in1 and in2 from the photocouplers 102a and 102b are both "1 (high)", and the output signal out is "0 (low)". Also, when the port PT1 is unconnected and the port PT2 is connected, if the input signal in1 from the photocoupler 102a is "1 (high)" and the input signal in2 from the photocoupler 102b is "0 (low)", the output signal out is "0 (low)".

[0055] Also, when port PT1 is connected and port PT2 is not connected, if the input signal in1 from photocoupler 102a is "0 (low)" and the input signal in2 from photocoupler 102b is "1 (high)", the output signal out will be "1 (high)". When ports PT1 and PT2 are both connected, the input signals in1 and in2 from photocouplers 102a and 102b will both be "0 (low)", and the output signal out will maintain its previous state. In this case, if the previous output signal out was "0 (low)", it will remain "0 (low)", and if the previous output signal out was "1 (high)", it will remain "1 (high)".

[0056] That is, the state holding circuit 1045 has a configuration for holding an output state, and when the output signal from the NOR circuit 1043 is "0 (low)", it newly holds the output signal from the AND circuit 1044 and outputs this. However, when the output signal from the NOR circuit 1043 is "1 (low)", the state holding circuit 1045 does not newly hold the output signal from the AND circuit 1044, but maintains the currently held state so as to output it.

[0057] Furthermore, the relay circuit 103 of this embodiment switches to select port PT2 when the output signal out from the state holding circuit 1045 is "0 (low)", and switches to select port PT1 when the output signal out is "1 (high)". Here, switching to select port PT2 means that the relay circuit 103 selects input terminals b and e, and switching to select port PT1 means that the relay circuit 103 switches to select input terminals a and d.

[0058] As a result, when no power supply voltage is supplied from either port PT1 or PT2, the relay circuit 103 is switched so as to apply the power supply voltage from port PT2 as a specified port to the class discrimination circuit / power supply circuit 107. In this embodiment, as described above, the port PT2 is normally connected to a power supply hub on the network side. When a power supply voltage is supplied from one of the ports PT1 and PT2, the relay circuit 103 is switched so as to apply the power supply voltage of the one port to the class discrimination circuit / power supply circuit 107. Therefore, when power is supplied only through port PT1, the relay circuit 103 is switched so as to connect port PT1 to the class discrimination circuit / power supply circuit 107. When power is supplied only through port PT2, the relay circuit 103 is switched so as to connect port PT2 to the class discrimination circuit / power supply circuit 107.

[0059] Furthermore, when the power supply voltage is being supplied from both ports PT1 and PT2, the relay circuit 103 is switched so as to maintain the previous connection state. That is, if power was being supplied through port PT1 until then, the state of the relay circuit 103 is maintained (retained) so as to maintain the state in which port PT1 is connected to the class discrimination circuit / power supply circuit 107. Also, if power was being supplied through port PT2 until then, the state of the relay circuit 103 is maintained (retained) so as to maintain the state in which port PT2 is connected to the class discrimination circuit / power supply circuit 107.

[0060] [Summary of the IP telephone of the embodiment] In an IP telephone set 4 having two LAN ports PT1 and PT2, the following three problems must be solved in order to realize PoE power supply to multiple ports. (1) Ensuring insulation between ports, (2) A method for detecting the connection of a powered hub to each port and a method for detecting ports when no power is being supplied, and (3) Switching control when powered hubs are connected to multiple ports at the same time.

[0061] (1) As for ensuring insulation between ports, as described with reference to Figs. 4 and 5, the power supply voltage from port PT1 and the power supply voltage from port PT2 are applied to the class discrimination circuit / power supply circuit 107 via the relay circuit 103 (103a, 103b). For ports to which no power supply voltage is supplied, the relay circuit 103 (103a, 103b) is opened by the power supply switching circuit 104 to ensure insulation between the class discrimination circuit / power supply circuit 107 and other ports. Since the input signal to the power supply switching circuit 104 is input from the ports PT1 and PT2, insulation is ensured between the ports PT1 and PT2 and the power supply switching circuit 104 using the photocouplers 102a and 102b. This allows power to be supplied from either port PT1 or PT2, and prevents the other port from being affected even if a surge current is mixed in either port PT1 or port PT2 for some reason.

[0062] In addition, (2) the method of detecting the connection of an inductive hub to each port and the method of detecting a port when no power is being supplied can be realized by the power supply switching circuit 104. The power supply switching circuit 104 can appropriately distinguish a state in which a power supply hub is not connected to either port PT1 or PT2, a state in which a power supply hub is connected to only one of ports PT1 or PT2, and a state in which a power supply hub is connected to both ports PT1 and PT2. Based on the result of this determination, the power supply switching circuit 104 can appropriately control the switching of the relay circuit 103 (103a, 103b).

[0063] In addition, the power supply switching circuit 104 must control the switching of the relay circuit 103 (103a, 103b) before the power supply voltage is applied to the class discrimination circuit / power supply circuit 107. For this reason, when there is no power supply, the power supply hub 3 cannot receive a current sufficient to drive the relay circuit 103 (103a, 103b). Therefore, in order to obtain the current required to drive the relay circuit 103 (103a, 103b), a large-capacity capacitor 106 such as an electric double-layer capacitor is provided inside the device. This allows a drive current to be supplied to the relay circuit 103 (103a, 103b) when the connection of the power supply hub 3 is detected, and switching control can be performed. In addition, the large-capacity capacitor 106 is made capable of being charged by the power supply voltage from the power supply hub through the charging circuit 105, and by a power supply voltage from an external power source other than the power supply voltage from the power supply hub. This allows the power supply switching circuit 104 and the relay circuit 103 (103a, 103b) to operate appropriately.

[0064] Also, (3) switching control when multiple ports are connected to power supply hubs at the same time can be handled by the power supply switching circuit 104. In particular, the function of the state holding circuit 1045 of the power supply switching circuit 104 is important. In the initial state, the relay circuit 103 (103a, 103b) of the PoE power supply unit 4011 of the IP telephone 4 in this embodiment is switched to supply power from port PT2 (NW) when not supplying power or when the port is not connected. Also, the power supply switching circuit 104 is a circuit whose output changes as shown in the operation truth table in FIG. 6.

[0065] As a result, when neither port PT1 nor PT2 is connected, or when a power supply hub is connected only to port PT2, the relay is controlled to supply power from port PT2. Also, when only port PT1 (PC) is connected, the relay is controlled to supply power from port PT1. Furthermore, when both ports PT1 and PT2 are connected to a power supply hub, the operation is to maintain the power supply state from the port that last (immediately before) supplied power. Therefore, when a power supply hub 3 is connected to port PT2 (NW) while power is being supplied from port PT1 (PC), the power supply switching circuit 104 controls the relay circuit 103 (103a, 103b) to continue supplying power from port PT1 (PC).

[0066] In this embodiment, the power supply switching circuit 104 is composed of a general-purpose logic circuit and a plurality of passive components, and as described with reference to Fig. 4, power is supplied from a large-capacity capacitor 106 inside the device. Also, assume that the large-capacity capacitor 106 has naturally discharged due to a long period of non-use (for example, several months to several years or more). Even in this case, since the relay circuit 103 (103a, 103b) is connected to the port PT2 (NW), it is possible to receive PoE power supply from the port PT2 (NW) even after the discharge.

[0067] [Effects of the embodiment] As described above, the IP telephone 4 of this embodiment can receive PoE power appropriately regardless of whether a power supply hub is connected to the port PT1 or PT2. In other words, whether a non-powered device such as a PC is connected to the port PT1 or PT2, the non-powered device such as a PC can be appropriately connected to the network side. In other words, since a power supply device or a non-powered device can be connected to either the port PT1 or PT2 of the IP telephone 4, the degree of freedom of wiring can be improved. In addition, since there is no risk of inserting the LAN cable incorrectly, the efficiency and speed of wiring work can be improved. In addition, insulation can be ensured between the port PT1 side and the port PT2 side, and the influence of a surge current generated on either port side can be prevented from affecting the other port side.

[0068] [Variations] The IP telephone 4 in the above embodiment has been described as having two LAN ports PT1 and PT2, but this is not limited to this. The present invention can also be applied to an IP terminal device having three or more LAN ports. In this case, a relay circuit is provided so that one of the three or more LAN ports can be selected to apply a power supply voltage to the class discrimination circuit / power supply circuit 107. Furthermore, the power supply switching circuit is configured to satisfy all of the following three conditions.

[0069] The first condition is that when no power supply devices such as power supply hubs are connected to any of the LAN ports, or when some devices are connected but power is not being supplied through any of the LAN ports, the power supply is supplied from one predetermined LAN port. The second condition is that when there is only one port to which power voltage is being supplied, the relay circuit is switched so that only the power supply voltage from that one port is applied to the class discrimination circuit / power supply circuit 107. The third condition is that when power voltage is being supplied through multiple ports, the power supply state from the port that last (immediately before) received power is maintained. By satisfying these conditions, the present invention can be applied to an IP terminal device having three or more LAN ports, and the same effects as those of the IP telephone 4 of the above-mentioned embodiment can be obtained.

[0070] In the IP telephone 4 according to the above embodiment, the connection between each port and the power supply switching circuit is described as using a photocoupler, but this is not limited to this. The connection between each port and the power supply switching circuit can be made using various insulating elements such as an isolator element or a transformer element.

[0071] In the above embodiment, the IP terminal device of the present invention is applied to the IP telephone 4, but the present invention is not limited to this. For example, the present invention can be applied to various electronic devices that communicate using IP, such as IP camera door phones, Web cameras, and wireless LAN access points, and that have a PoE power supply function.

[0072] Furthermore, in the IP telephone set 4 according to the above-described embodiment, as explained with reference to Fig. 4, the large-capacity capacitor 106 is used. This large-capacity capacitor may be an electric double layer capacitor or various secondary batteries.

[0073] In addition, in the IP telephone 4 of the above embodiment, as explained with reference to FIG. 4, the charging circuit 105 and the large-capacity capacitor 106 are used, but the present invention is not limited to this. A power supply circuit using various primary batteries as a power source may be used. In this case, it is sufficient to make it possible to replace the primary battery when it is completely discharged. In this case, there is also no need to provide a charging function using a power supply voltage or an external power source. [Explanation of symbols]

[0074] 1...network, 2...main unit, 3...power supply hub, 301...preceding device side port, 302...subceding device side port, 4, 4(1), 4(2), ..., 4(n)...IP telephone, PT1...port, PT2...port, 401...LAN interface unit, 4011...PoE power supply unit, 101a, 101b...diode bridge, 102a, 102b...photocoupler, 103, 103a, 103b...relay circuit, 104...power supply switching circuit, 10 41...XOR circuit, 1042...NOT circuit, 1043...NOR circuit, 1044...AND circuit, 1045...state retention circuit, 105...charging circuit, 106...large-capacity capacitor, 107...classification circuit / power supply circuit, 402...packet transmission / reception unit, 403...audio codec, 404...handset, 4041...speaker, 4042...microphone, 410...control unit, 411...operation unit, 5, 5(1), 5(2), ..., 5(n)...PC

Claims

1. a power supply circuit that receives an input power supply voltage and generates an output power supply voltage to be supplied to each unit; Two or more LAN (Local Area Network) ports; a relay circuit to which the power supply lines of the two or more LAN ports are connected and which switches which of the LAN ports' power supply lines is to be connected to the power supply circuit; a power supply switching circuit to which the power supply lines of the two or more LAN ports are connected and which performs switching control of the relay circuit based on a state of a power supply voltage applied through the power supply lines of the two or more LAN ports; Equipped with The power supply switching circuit includes: when no power supply voltage is supplied from any of the two or more LAN ports, a power supply line of a predetermined LAN port among the two or more LAN ports is connected to the power supply circuit, and power supply lines of other LAN ports are not connected to the power supply circuit; When a power supply voltage is supplied from one of the two or more LAN ports, the power supply line of the one LAN port is connected to the power supply circuit, and the power supply lines of the other LAN ports are not connected to the power supply circuit; When power supply voltage is being supplied from a plurality of LAN ports among the two or more LAN ports, the power supply line of the LAN port that was previously receiving power is maintained connected to the power supply circuit, and the power supply lines of the other LAN ports are maintained unconnected to the power supply circuit, The relay circuit is controlled so as to maintain the previous connection state.

1. An IP terminal device comprising:

2. 2. The IP terminal device according to claim 1, Each of the two or more LAN ports and the power supply switching circuit are connected through an insulating element.

1. An IP terminal device comprising:

3. 3. An IP terminal device according to claim 1, a drive circuit for supplying drive power to the power supply switching circuit; 1. An IP terminal device comprising:

4. 4. An IP terminal device according to claim 3, The drive circuit includes a large-capacity capacitor for supplying drive power, and a charging circuit for charging the large-capacity capacitor using one or both of a power supply voltage from an external power supply and a power supply voltage from the power supply circuit.

1. An IP terminal device comprising:

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