ELECTRONIC DEVICE

According to one embodiment, an electronic device includes a connector, a first determination unit, and a first switching unit. The connector includes a plurality of terminals for being electrically connected to a peripheral device. The first determination unit determines whether or not a peripheral device compatible with an own device is connected to the connector, based upon an electrical state of a terminal that is not used in a terminal configuration of the own device among the plurality of terminals. The first switching unit is provided on a transmission line connecting the terminal of the connector and an electric circuit of the own device, electrically connects the transmission line when the first determination unit determines that the peripheral device compatible with the own device is connected, and electrically disconnects the transmission line when the first determination unit determines that a non-compatible peripheral device is connected.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-221614, filed in Dec. 6, 2019, the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to an electronic device and a connection method.

BACKGROUND

In a POS terminal of a related art, a technology referred to as low voltage differential signaling (LVDS) is adopted for a graphic interface that processes a display signal. However, since LVDS will not be supported in the future, a change to a USB Type-C standard is considered. Specifications of the graphic interface are changed to the USB Type-C standard, whereby a general-purpose connector (a receptacle) and a general-purpose plug cable that comply with the standard can be used for a transmission unit of the display signal.

Meanwhile, a POS display device is provided with a touch panel as well as a display. A control signal of the touch panel passes through the general-purpose plug cable that connects a control unit main body of the POS terminal and the POS display device together with the display signal. Therefore, a terminal of the general-purpose connector that connects the general-purpose plug cable has a terminal configuration unique to the POS terminal, and is different from a standard terminal configuration of the USB Type-C standard. When a display device that uses the general-purpose plug cable and has the standard terminal configuration is connected to the general-purpose connector, there is a problem that a circuit may malfunction or may be short-circuited due to a difference in the terminal configuration.

DETAILED DESCRIPTION

According to one embodiment, there is provided an electronic device capable of preventing electrical connection between devices of connection destinations when connecting the devices having different terminal configurations of connectors.

In general, according to one embodiment, an electronic device includes a connector, a first determination unit, and a first switching unit. The connector includes a plurality of terminals for being electrically connected to a peripheral device. The first determination unit determines whether or not a peripheral device compatible with an own device is connected to the connector, based upon an electrical state of a terminal that is not used in a terminal configuration of the own device among the plurality of terminals. The first switching unit is provided on a transmission line connecting the terminal of the connector and an electric circuit of the own device, electrically connects the transmission line when the first determination unit determines that the peripheral device compatible with the own device is connected, and electrically disconnects the transmission line when the first determination unit determines that a non-compatible peripheral device is connected. According to another embodiment, a connection method involves determining whether or not a peripheral device compatible with an electronic device is connected to a connector including a plurality of terminals for being electrically connected to the peripheral device, based upon an electrical state of a non-use terminal that is not used in a terminal configuration of the electronic device among the plurality of terminals; electrically connecting a transmission line connecting a terminal of the plurality of terminals of the connector and an electric circuit of the electronic device when determining that the peripheral device compatible with the electronic device is connected; and electrically disconnecting the transmission line when determining that a non-compatible peripheral device is connected.

Hereinafter, embodiments of an electronic device will be described in detail with reference to the accompanying drawings. In the embodiment described below, a peripheral device is used as a display device, and an application example of the electronic device and the display device to a point of sales (POS) device is shown.

FIG. 1is an external perspective view illustrating an example of a commodity reading apparatus. A commodity reading apparatus1is an example of a POS device, and includes a POS display device1-1and a main body unit1-2as illustrated inFIG. 1. The main body unit1-2corresponds to the “electronic device”, and the commodity reading apparatus1corresponds to a “display apparatus”. The POS display device1-1corresponds to a “peripheral device” or a “corresponding device” as one of the peripheral device and a “dedicated display device”.

The POS display device1-1includes a display10, a touch panel11, a speaker, and the like. The POS display device1-1is electrically connected to the main body unit1-2by a general-purpose plug cable (not illustrated). An electric wire (a signal line) for transmitting various signals and an electric signal such as driving power is housed in the general-purpose plug cable. The POS display device1-1can be attached to and detached from the main body unit1-2, and can be replaced with another display by removing and inserting the general-purpose plug cable.

The display10is a display such as a liquid crystal display, and displays various screen data on a display screen such as a liquid crystal according to a display signal from a control unit of the main body unit1-2. For example, registration screen data in which a commodity selection button for registering a commodity by a touch input is disposed are displayed. For example, the touch panel11is a touch panel such as an electrostatic capacity system, and is provided on the display screen of the display10. For example, when an operator touches the commodity selection button on the display screen, the touch panel11detects the touch operation of the operator and outputs a signal indicating coordinates on the display screen to the control unit of the main body unit1-2.

The main body unit1-2includes a reading scanner13such as a laser scanner. The reading scanner13is a scanner for reading a barcode attached to a commodity.

A housing (a second housing)12-2of the main body unit1-2houses a motherboard2(refer toFIG. 2) for controlling the whole commodity reading apparatus1. The motherboard2is mounted with the control unit and a controller for each unit, for example, a controller for the POS display device1-1. In the embodiment, a USB Type-C standard is adopted as an interface system for display signal processing. Therefore, a USB Type-C compliant connector is used for a connector31(refer toFIG. 2) as a receptacle on the side of the motherboard2and a connector as a receptacle on the side of the display device1-1. A USB Type-C compliant general-purpose plug cable is used to connect a signal line between the connectors.

Next, a configuration of the motherboard2will be described.FIG. 2is a hardware block diagram of the motherboard2. The motherboard2illustrated inFIG. 2includes a CPU20, a BIOS-ROM21, a memory22, a chipset23, an external storage apparatus24, a scanner controller25, a communication I/F26, a first switching control unit27, a first switching unit28, a second switching control unit29, a second switching unit30, a connector31, and a power supply unit P.

The CPU20is a central processing unit and executes various programs to generate data and output a control signal.

The BIOS-ROM21is a read only memory (ROM) that stores a basic input and output system (BIOS).

The memory22is a random access memory (RAM) used as a work region of the CPU20.

The chipset23is an example of an electronic circuit. The chipset23includes a north bridge and a south bridge, and performs memory control and control of an I/O device. In the embodiment, a USB controller230and a VGA controller231are mounted on the chipset23. The USB controller230controls the touch panel11of a USB device (refer toFIG. 1), and processes an input signal from the touch panel11. The VGA controller231generates display data, and outputs the display signal to the display10(refer toFIG. 1).

The external storage apparatus24is an HDD and a flash ROM, and stores a control program, commodity information for inquiring a commodity name, and screen data.

The scanner controller25is connected to the reading scanner13(refer toFIG. 1). The scanner controller25drives the reading scanner13to read barcode information.

The communication I/F26is a communication interface for transmitting the commodity information read by the commodity reading apparatus1to a POS register.

The first switching control unit27outputs a predetermined control signal to the first switching unit28in response to whether the display device connected to the connector31via the general-purpose plug cable is a non-compatible device of its own device or a compatible device thereof. For example, when the display device of the non-compatible device, which is not the POS display device1-1corresponding to the compatible device of its own device, is connected to the connector31, the first switching control unit27outputs a control signal for controlling the first switching unit28to be “disconnected”. When the POS display device1-1corresponding to the compatible device of its own device is connected to the connector31, the first switching control unit27outputs a control signal for controlling the first switching unit28to be “connected”. Hereinafter, a case where the display device of the non-compatible device is used as a USB Type-C compliant general-purpose display device is described as an example.

The first switching unit28electrically connects or disconnects a signal line between the motherboard and the display device of a connection destination by, for example, switching a switch circuit, based upon an input of the control signal from the first switching control unit27.

The second switching control unit29outputs a control signal for switching a terminal group of the connector31connected to the chipset23to the second switching unit30in response to a connection direction of a plug of the general-purpose plug cable connected to the connector31. As will be described later, since the USB Type-C compliant connector31does not distinguish between up and down, it is possible to connect the plug upside down. The second switching control unit29detects a direction of the plug connected to the connector31, and outputs a control signal for switching the terminal of the connector31connected to the chipset23to the second switching unit30in response to the detected connection direction of the plug.

The second switching unit30selectively connects one of the pair of connection terminal groups provided in the connector31to the chipset23based upon the input of the control signal from the second switching control unit29. The second switching unit30switches the connection terminal group to be connected to the chipset23by, for example, switching the switch circuit.

The connector31is a receptacle that complies with the USB Type-C standard and includes24terminals. A signal line such as a display signal, a touch panel control signal, and a power supply for a display device is connected to each terminal.

The power supply unit P appropriately performs voltage conversion on the electric power of a commercial power supply to supply the electric power to each unit. For example, the power supply unit P supplies the electric power for the display device to the POS display device1-1via the general-purpose plug cable.

Next, a terminal configuration of the connector31, that is, a terminal configuration of a POS type will be described with reference toFIGS. 3 and 4.

FIG. 3is a diagram illustrating an example of an external shape of the connector31(including a shape of a terminal connection unit).FIG. 3is a schematic front view of the terminal connection unit of the connector31, and terminal numbers (Pin1to Pin24) are added to positions of the respective terminals. The shape of the connector31illustrated inFIG. 3complies with the USB Type-C standard. Therefore, the general-purpose plug cable used in the general-purpose display device can be used for the connector31.

FIG. 4is a comparison diagram of a terminal configuration of the connector31and a terminal configuration of a general-purpose type. In this example, as the terminal configuration of the general-purpose type, a terminal configuration of the general-purpose display device that complies with the USB Type-C standard is shown.FIG. 4shows a list of terminal numbers of the terminals provided in the connector31. A general-purpose type list showing an example of the terminal configuration of the general-purpose type and a POS type list showing an example of the terminal configuration of the POS type are shown in association with each terminal number of a terminal number list.

As illustrated inFIG. 3, the connector31of the USB Type-C standard includes a terminal group of “Pin1” to “Pin12” disposed at an upper stage and a terminal group of “Pin13” to “Pin24” disposed at a lower stage. Even though the upper and lower parts of the plug are switched and connected, these terminal groups are symmetrically disposed to be able to be connected to the same general-purpose type terminal.

Specifically, in the terminal configuration of the general-purpose type, “Pin1” and “Pin12” are terminals for ground (hereinafter abbreviated as GND). “Pin1” and “Pin12” correspond to “Pin13” and “Pin24”. “Pin2” and “Pin3” are terminals for a data path (TX). “Pin2” and “Pin3” correspond to “Pin14” and “Pin15”. “Pin4” and “Pin9” are terminals for bus power. “Pin4” and “Pin9” correspond to “Pin16” and “Pin21”. “Pin5” is a terminal for detecting a plug configuration. “Pin5” corresponds to “Pin17”. “Pin6” and “Pin7” are terminals for a data path (USB 2.0). “Pin6” and “Pin7” correspond to “Pin18” and “Pin19”. “Pin8” is a terminal for a sideband. “Pin8” corresponds to “Pin20”. “Pin10” and “Pin11” are terminals for a data path (RX). “Pin10” and “Pin11” correspond to “Pin22” and “Pin23”.

That is, in the connector31of the USB Type-C standard, the terminal group of “Pin1” to “Pin12” and the terminal group of “Pin13” to “Pin24” form a pair of terminal groups that can be connected even though the directions of the plug are switched. In the following, a state in which the plug is connected to the terminal group of “Pin1” to “Pin12” is also referred to as a “forward direction”, and a state in which the plug is connected to the terminal group of “Pin13” to “Pin24” is also referred to as a “reverse direction”. The terminal group of “Pin1” to “Pin12” is also referred to as a “forward direction side”, and the terminal group of “Pin13” to “Pin24” is also referred to as a “reverse direction side”.

On the other hand, in the terminal configuration of the POS type, “Pin2” and “Pin3”, or “Pin14” and “Pin15” are used for transmitting the display signal. In the terminal configuration of the POS type, “Pin6” and “Pin7”, or “Pin18” and “Pin19” are used for controlling the USB device (the touch panel11in this example (refer toFIG. 1)). In the terminal configuration of the POS type, “Pin1” or “Pin13” is used for GND, and “Pin4” or “Pin16” is used for power supply to the display device1-1.

In the terminal configuration of the POS type, “Pin8” and “Pin12” on the forward direction side or “Pin20” and “Pin24” on the reverse direction side are used for a connection direction detection for detecting whether the plug is connected to the forward direction side or the reverse direction side. A symbol “-” shown in a POS type list32indicates that Pin is not used in the POS type.

In this manner, in the terminal configuration of the POS type of the embodiment, “Pin5”, “Pin9” to “Pin11”, “Pin17”, “Pin21” to “Pin23” are not used for electrical connection with the display device1-1. Therefore, the main body unit1-2detects which one of the compatible device and the general-purpose display device that complies with the USB Type-C standard (the non-compatible device) is connected, based upon electrical states of the terminals of “Pin5”, “Pin9” to “Pin11”, “Pin17”, “Pin21” to “Pin23”. Hereinafter, the terminals of “Pin5”, “Pin9” to “Pin11”, “Pin17”, and “Pin21” to “Pin23” are also collectively referred to as “monitor terminals”.

Next, a configuration example of the first switching control unit27, the first switching unit28, the second switching control unit29, and the second switching unit30will be described.FIG. 5is a diagram illustrating a configuration example of the first switching control unit27, the first switching unit28, the second switching control unit29, and the second switching unit30. Here, the first switching control unit27is an example of a first determination unit. The first switching unit28is an example of a first switching unit. The second switching control unit29is an example of a second determination unit. The second switching unit30is an example of a second switching unit. InFIG. 5, a plurality of sets of electric wires relating to various types of transmission are shown by one line.

As illustrated inFIG. 5, the first switching unit28includes a forward direction side switch281and a reverse direction side switch282. The forward direction side switch281includes single-throw type switches SW11to SW14and is connected between the forward direction side terminal of the connector31and the second switching unit30. Specifically, one end side of the switch SW11is connected to “Pin1” of the connector31, and the other end side of the switch SW11is connected to a line L11that connects the second switching unit30and the switch SW11. One end side of the switch SW12is connected to “Pin2” and “Pin3” of the connector31, and the other end side of the switch SW12is connected to a line L21that connects the second switching unit30and the switch SW12. One end side of the switch SW13is connected to “Pin4” of the connector31, and the other end side of the switch SW13is connected to a line L31that connects the second switching unit30and the switch SW13. One end side of the switch SW14is connected to “Pin6” and “Pin7” of the connector31, and the other end side of the switch SW13is connected to a line L41that connects the second switching unit30and the switch SW14.

The reverse direction side switch282includes single-throw type switches SW21to SW24, and is connected between the reverse direction side terminal of the connector31and the second switching unit30. Specifically, one terminal of the switch SW21is connected to “Pin13” of the connector31, and the other terminal is connected to a line L12that connects the second switching unit30and the switch SW21. One terminal of the switch SW22is connected to “Pin14” and “Pin15” of the connector31, and the other terminal is connected to a line L22that connects the second switching unit30and the switch SW22. One terminal of the switch SW23is connected to “Pin16” of the connector31, and the other terminal is connected to a line L32that connects the second switching unit30and the switch SW23. One terminal of the switch SW24is connected to “Pin18” and “Pin19” of the connector31, and the other terminal is connected to the line L42that connects the second switching unit30and the switch SW24.

The forward direction side switch281and the reverse direction side switch282switch on or off each switch in response to a control signal Y1outputted from the first switching control unit27, whereby the connector31and the second switching unit30(the chipset23) are electrically connected or disconnected.

The first switching control unit27is connected to the monitor terminal of the connector31. The first switching control unit27monitors a voltage value applied to the monitor terminal as an input signal X1as the electrical state of the monitor terminal. The first switching control unit27is connected to the first switching unit28(the forward direction side switch281and the reverse direction side switch282), and outputs the control signal Y1for turning on or off all the switches of the first switching unit28in response to the input signal X1.

In the terminal configuration of the POS type used in the embodiment, as illustrated inFIG. 4, none of the monitor terminals is used. Therefore, when the POS display device1-1is connected to the connector31, the voltage value at the monitor terminal becomes zero or almost zero. On the other hand, when the general-purpose display device is connected to the connector31, a voltage value in response to a function of each terminal is applied to the monitor terminal as the input signal X1.

Next, the first switching control unit27determines whether or not the display device connected to the connector31is the POS display device1-1based upon the voltage value of the input signal X1, and outputs the control signal Y1in response to the determination result to the first switching unit28. Specifically, when the voltage value of the input signal X1is zero or almost zero, the first switching control unit27determines that the POS display device1-1is connected, and outputs the control signal Y1for turning on all the switches of the first switching unit28. When the voltage value of the input signal X1is equal to or greater than a threshold value which is greater than zero, the first switching control unit27determines that the general-purpose display device is connected, and outputs the control signal Y1for turning off all the switches of the first switching unit28.

Accordingly, when the general-purpose display device is connected to the connector31, the first switching control unit27can disconnect the chipset23and the connector31so that the chipset23and the connector31are not electrically connected to each other. When the POS display devicel-1is connected to the connector31, the first switching control unit27can electrically connect the chipset23and the connector31.

The first switching control unit27may be configured to monitor all of the monitor terminals, or may be configured to monitor some of the terminals. For example, the first switching control unit27may be configured to monitor Pin5and Pin17that are used for detecting the plug configuration with the general-purpose type among the monitor terminals.

The second switching unit30includes double-throw type switches SW31to SW34, and is connected between the first switching unit28and the chipset23. Specifically, two terminals on the switching side of the switch SW31are connected to the line L11of the switch SW11and the line L12of the switch SW21, and a remaining one terminal is connected to a line L1that connects the chipset23and the switch SW31. Two terminals on the switching side of the switch SW32are connected to the line L21of the switch SW12and the line L22of the switch SW22, and a remaining one terminal is connected to a line L2that connects the chipset23and the switch SW32. Two terminals on the switching side of the switch SW33are connected to the line L31of the switch SW13and the line L32of the switch SW23, and a remaining one terminal is connected to a line L3that connects the chipset23and the switch SW33. Two terminals on the switching side of the switch SW34are connected to the line L41of the switch SW14and the line L42of the switch SW24, and a remaining one terminal is connected to a line L4that connects the chipset23and the switch SW34.

The second switching unit30switches the connection destination to either one of the two terminals on the switching side in response to a control signal Y2outputted from the second switching control unit29, whereby the chipset23is electrically connected to the forward direction side or the reverse direction side of the connector31.

The second switching control unit29is connected to Pin8and Pin12of the connector31. The second switching control unit29detects (determines) the connection direction of the plug connected to the connector31based upon the electrical state of the Pin12. Specifically, the second switching control unit29outputs an output signal X2via Pin8, and receives an input of an input signal X2′ corresponding to the output signal X2via Pin12. Next, the second switching control unit29determines the connection direction of the plug to the connector31based upon a reception result of the input signal X2′, and the control signal Y2for switching all the switches of the second switching unit30to the forward direction side or the reverse direction side of the connector31is outputted in response to the connection direction.

FIG. 6is a diagram illustrating a configuration example relating to the detection of the connection direction of the plug of the second switching control unit29. As described above, the second switching control unit29outputs the output signal X2via “Pin8”. The output signal X2is inputted to a terminal T1connected by the terminal “Pin8” and a signal line K1.

The POS display device1-1loops back the output signal X2inputted to the terminal T1to a terminal T2connected to the terminal “Pin12” of the main body unit1-2by a signal line K2by a loopback unit60. The loopback unit60can be realized by, for example, connecting the terminal T1and the terminal T2of the POS display device1-1by a short-circuiting unit61such as a lead wire and pattern wiring.

According to the above-described configuration, when the plug is connected to the connector31in the forward direction, the output signal X2is inputted to the terminal “Pin12” of the main body unit1-2as the input signal X2′ by the above-described loopback unit60. On the other hand, when the plug is connected to the connector31in the reverse direction, the terminals T1and T2of the display device1-1are connected to the terminals “Pin20” and “Pin24” of the main body unit1-2, such that the output signal X2is not transmitted to the display device1-1and the input signal X2′ is not also looped back.

The second switching control unit29detects the connection direction of the plug connected to the connector31based upon whether or not the input signal X2′ is looped back, and outputs the control signal Y2in response to the detection result to the second switching unit30. Specifically, when the input signal X2′ is looped back, the second switching control unit29determines that the plug is connected to the forward direction side, and outputs the control signal Y2for switching all the switches of the second switching unit30to the forward direction side of the connector31. When the input signal X2′ is not looped back, the second switching control unit29determines that the plug is connected to the reverse direction side, and outputs the control signal Y2for switching all the switches of the second switching unit30to the reverse direction side of the connector31.

In this manner, when the POS display device1-1is connected to the connector31, the second switching control unit29switches the connection destination of the second switching unit30to the forward direction side or the reverse direction side in response to the connection direction of the plug. Accordingly, since the POS display device1-1and the chipset23are electrically connected to each other, it becomes possible to transmit an electric signal between the main body unit1-2and the POS display device1-1.

In the embodiment, the second switching control unit29detects (determines) the connection direction of the plug by using “Pin8” and “Pin12” on the forward direction side, and maybe configured to determine the connecting direction of the plug by using “Pin20” and the “Pin24” on the reverse direction side. The second switching control unit29outputs the output signal X2to “Pin8” on the forward direction side and “Pin20” on the reverse direction side, and may determine the connection direction of the plug in response to whether the terminal receiving the input signal X2′ is “Pin12” on the forward direction side or “Pin24” on the reverse direction side.

Hereinafter, an operation procedure of the commodity reading apparatus1when the main body unit1-2and the display device are connected by the general-purpose plug cable will be described.FIG. 7is a flowchart illustrating an example of the operation procedure of the commodity reading apparatus1.

First, the first switching control unit27waits until the display device is connected via the connector31(ACT11: No). Here, the first switching control unit27outputs the control signal Y1for turning off all the switches of the first switching unit28during the standby in ACT11.

Next, when the display device is connected to the connector31of the main body unit1-2(ACT11: Yes), the first switching control unit27determines whether the display device of the connection destination is a POS type display device or a general-purpose display device (a non-compatible display device) based upon a voltage value (the input signal X1) of the monitor terminal (ACT12).

Here, when the display device of the connection destination is the general-purpose display device (ACT13; No), the first switching control unit27outputs the control signal Y1for turning off all the switches of the first switching unit28. Accordingly, the first switching unit28electrically disconnects the general-purpose display device by turning off all the switches (ACT14), and terminates this processing.

On the other hand, when the display device of the connection destination is the POS type display device (ACT13; Yes), the first switching control unit27outputs the control signal Y1for turning on all the switches of the first switching unit28. Accordingly, the first switching unit28electrically connects the POS type display device by turning on all the switches (ACT15).

Next, the second switching control unit29determines the connection direction of the plug connected to the connector31based upon the loopback (the input signal X2′) of the output signal X2outputted to the display device via “Pin8” (ACT16).

Here, when the connection direction of the plug is the forward direction (ACT17; Yes), the second switching control unit29connects all the switches of the second switching unit30to the forward direction side switch281of the first switching unit28(ACT18), and terminates this processing. When the connection direction of the plug is the reverse direction (ACT17; Yes), the second switching control unit29connects all the switches of the second switching unit30to the reverse direction side switch282of the first switching unit28(ACT19), and terminates this processing.

As described above, in the main body unit1-2, the type of the display device connected to the connector31is determined based upon the electrical state of the monitor terminal of the connector31. When the POS type display device is connected to the connector31, the main body unit1-2electrically connects a transmission line between the chipset23and the connector31, and when the general-purpose display device is connected to the connector31, the main body unit1-2electrically cut off the transmission line between the chipset23and the connector31. Therefore, the main body unit1-2can prevent electrical connection with the device of the connection destination when connecting a device having a different terminal configuration of a connector.

When the POS type display device is connected to the connector31via the general-purpose plug cable, the main body unit1-2determines the connection direction of the plug connected to the connector31based upon the electrical state of a predetermined terminal (Pins8and12or Pins20and24) provided in any one of the terminal groups among the pair of terminal groups provided in the connector31. Next, the main body unit1-2switches the connection destination of the chipset23to the forward direction side or the reverse direction side of the connector31in response to the determined connection direction of the plug. Accordingly, when the POS type display device is connected to the connector31, the main body unit1-2can electrically connect the chipset23and the POS type display device regardless of the direction of the plug. Therefore, it is possible to effectively utilize characteristics of the general-purpose plug cable that complies with the USB Type-C standard.

In the embodiment, as the terminal configuration of the POS type, a form using the terminal configuration illustrated inFIG. 4is described, but the terminal configuration is not limited thereto. For example, when a sound output is performed by using a speaker provided in the display device, a terminal for the sound output may be secured.

In the embodiment, the first switching unit28switches the connection and disconnection of the transmission lines relating to Pins1to4, Pins6, and7(Pins13to16and Pins18and19), but the transmission line to be connected and disconnected is not limited thereto. For example, when there is no electrical impact on mutual devices, the transmission line may be excluded from a target of the switching control. For example, Pin8and Pin12(Pin20and Pin24) used for detecting the connection direction of the plug may be included in the target of the switching control.

In the embodiment, the connection direction is determined by using the two terminals of Pins8and12(or Pins20and24), but the embodiment is not limited thereto. The connection direction may be determined by using any one of the terminals. In this case, when the POS type display device1-1receives the output signal X2via a terminal set for the determination of the connection direction, the POS type display device1-1loops back and outputs the output signal X2(the input signal X2′) by using the terminal.

In the embodiment, a form in which the second switching unit30is provided between the chipset23and the first switching unit28is described, but the second switching unit30may be provided between the first switching unit28and the second switching unit30. In this case, the second switching unit30connects the forward direction side of the connector31and the forward direction side switch281or the reverse direction side of the connector31and the reverse direction side switch282in response to the control signal Y2of the second switching control unit29.

In the embodiment, a form using the USB Type-C standard is described, but other standards may be used. For example, in the case of a Lightning (registered trademark) standard, in the same manner as that of the USB Type-C standard, since there is no distinction between the upper and lower parts of the connector portion and the upper and lower parts thereof can be connected upside down, the same configuration as that of the above-described embodiment can be applied.

In the embodiment, when the general-purpose display device is connected to the connector31, the general-purpose display device is not displayed, such that a user can recognize the connected display device is the general-purpose display device, and a notification unit for explicitly notifying that the connected display device is the general-purpose display device may be further provided. For example, the main body unit1-2may include a sound output apparatus that emits a beep sound or a buzzer sound as the notification unit. In this case, the notification unit is configured to emit the beep sound or the buzzer sound in association with the switch-off control signal Y1outputted from the first switching control unit27and the switch-off operation by the first switching unit28, whereby the user can be notified that the general-purpose display device is connected thereto.

In the embodiment, an application example to the main body unit and the display device of the commodity reading apparatus is shown as the electronic device and the display device, but the embodiment is not limited thereto. This may be applied to other POS devices. For example, the electronic device and the display device may be applied to a main body unit and a display device of a POS register. Further, the electronic device and the display device may be applied to a main body unit and a display device of a self-POS. When the display device is required to connect two display devices, one device for a store clerk and the other device for a customer, the electronic device and the display device may be respectively applied to the main body unit and the display device for the store clerk, and the main body unit and the display device for the customer.

In the embodiment, the configuration of the main body unit and the display device is described by taking the USB Type-C standard as a connection interface as an example. However, a device other than the display device may be connected to the main body unit as a peripheral device, and the device may be expanded to one that identifies the non-compatible device at the time of connection.