TWM461169U - Automatic serial switching device - Google Patents

Abstract

An automatic serial switching device comprises a RS232 connector, a RS485/RS422 connector, a RS232 voltage conversion circuit, a RS485/RS422 voltage conversion circuit, and an automatic switching circuit. The automatic switching circuit comprises a first diode and a second diode. The first diode and the second diode switch between conducting and non-conducting according to the voltage level of a RS232 level adjusting signal and a RS232 level adjusting signal to corresponding pass the RS232 level adjusting signal and the RS232 level adjusting signal. This invention performs automatically switching between RS232 and RS485/RS422 communication interface, and also improves convenience.

Description

Serial port automatic switching device

The present invention relates to a switching device, and more particularly to a serial port automatic switching device.

Referring to FIG. 1 , a conventional serial port switching device is suitable for data exchange between a host 19 and peripheral devices or instruments having a serial communication interface of RS232, RS485 or RS422, and the serial port switching device includes: an RS232 connector 11 An RS485/RS422 connector 12, a jumper 13, an RS485/RS422 conversion chip 14, and an RS232 conversion chip 15.

The communication signals belonging to the RS232, RS485 and RS422 communication interfaces are respectively accessed via the RS232 connector 11 and the RS485/RS422 connector 12, and then jumpers (jumper) 13 and RS485/RS422 conversion chips 14 are used to jump to switch different communication. The signal is output to the host 19.

However, when the serial port switching device is applied to the embedded system, it is very inconvenient. When the user needs to switch the communication interface, such as when switching from the RS232 communication interface to the RS485/RS422 communication interface, the chassis must be opened to adjust the jumper 13 to Switching communication interface is very important for system level products Not convenient.

Therefore, the purpose of the present invention is to provide a serial port automatic switching device that can solve the above problems.

Therefore, the novel serial port automatic switching device comprises an RS232 connector, an RS485/RS422 connector, an RS232 voltage conversion circuit, an RS485/RS422 voltage conversion circuit, and an automatic switch gate circuit.

The RS232 connector is used to connect a device with an RS232 serial communication interface to transmit an RS232 interface specification signal.

The RS485/RS422 connector is used to connect a device with RS485/RS422 serial communication interface to transmit a signal of RS485/RS422 interface specification.

The RS232 voltage conversion circuit is electrically connected to the RS232 connector to receive the RS232 interface specification signal from the RS232 connector, and voltage-converts the RS232 interface specification signal to obtain an RS232 level adjustment signal.

The RS485/RS422 voltage conversion circuit is electrically connected to the RS485/RS422 connector to receive the RS485/RS422 interface specification signal from the RS485/RS422 connector, and the RS485/RS422 interface specification signal is voltage-converted to obtain a RS485/RS422 level adjustment signal.

The automatic switch gate circuit includes a first diode and a second diode. The first diode has a cathode electrically connected to the RS232 voltage conversion circuit to receive the RS232 level adjustment signal, and an anode. The first The diode has a cathode electrically connected to the RS485/RS422 voltage conversion circuit to receive the RS485/RS422 level adjustment signal, and an anode electrically connected to the anode of the first diode.

The first diode and the second diode are respectively switched between the conduction and the non-conduction according to the RS232 level adjustment signal and the level of the RS485/RS422 level adjustment signal, so as to transmit the RS232 correspondingly. Level adjustment signal, the RS485/RS422 level adjustment signal.

21‧‧‧RS232 connector

22‧‧‧RS485/RS422 connector

3‧‧‧RS232 voltage conversion circuit

4‧‧‧RS485/RS422 voltage conversion circuit

5‧‧‧RS422 voltage conversion circuit

6‧‧‧Automatic switch gate circuit

61‧‧‧ Output

62‧‧‧First Diode

63‧‧‧Secondary diode

64‧‧‧resistance

65‧‧‧Power terminal

7‧‧‧Non-gate circuit

8‧‧‧Control circuit

9‧‧‧Host

Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: FIG. 1 is a schematic block diagram of a conventional serial port switching device; FIG. 2 is a schematic diagram of one of the novel serial port automatic switching devices. A schematic block diagram of a preferred embodiment; and FIG. 3 is a circuit diagram of an automatic switch gate circuit of the preferred embodiment.

Referring to FIG. 2, the preferred embodiment of the automatic serial port switching device is adapted to be connected to a host 9. The serial port automatic switching device comprises an RS232 connector 21, an RS485/RS422 connector 22, an RS232 voltage conversion circuit 3, and a The RS485/RS422 voltage conversion circuit 4, an RS422 voltage conversion circuit 5, an automatic switch gate circuit 6, an NOT gate circuit 7, and a control circuit 8.

The RS232 connector 21 is used to connect a device (not shown) having an RS232 serial communication interface to transmit an RS232 interface specification signal.

The RS485/RS422 connector 22 is configured to connect a device (not shown) having an RS485/RS422 serial communication interface to transmit a RS485/RS422 interface specification signal and receive an RS485 output signal or an RS422 output signal respectively. .

In the present embodiment, the RS232 connector 21 uses a standard DB9 connector, and the RS485/RS422 connector 22 uses a conventional pin header connector, but is not limited thereto.

The RS232 voltage conversion circuit 3 is electrically connected to the RS232 connector 21 to receive the RS232 interface specification signal from the RS232 connector 21, and voltage-converts the RS232 interface specification signal to obtain an RS232 level adjustment signal.

In this embodiment, the RS232 interface specification signal has a voltage range of -9V~+9V, and the RS232 voltage conversion circuit 3 receives and converts the RS232 interface specification signal into a TTL (Transistor-Transistor Logic) voltage signal, but Not limited to this.

The RS485/RS422 voltage conversion circuit 4 is electrically connected to the RS485/RS422 connector 22 to receive the RS485/RS422 interface specification signal from the RS485/RS422 connector 22, and to perform voltage conversion on the RS485/RS422 interface specification signal. To get an RS485/RS422 level adjustment signal.

The RS485/RS422 voltage conversion circuit 4 receives and outputs the RS485/RS422 level adjustment signal and one of the RS485 output signals according to a control signal.

In this embodiment, the RS485/RS422 interface specification message The voltage range of the number is 0~5V, and the RS485/RS422 voltage conversion circuit 4 receives the signal of the RS485/RS422 interface specification, and converts the signal of the RS485/RS422 interface specification into a TTL (Transistor-Transistor Logic) voltage signal. Form, but not limited to this.

The RS422 voltage conversion circuit 5 is electrically connected to the RS485/RS422 connector 22, receives and converts a voltage of an RS422 internal output signal, and outputs the corresponding RS422 output signal to the RS485/RS422 connector 22.

In this embodiment, the RS422 voltage conversion circuit 5 is a three-state logic, which can isolate the RS422 output signal and the conversion voltage, but is not limited thereto.

Referring to FIG. 2 and FIG. 3, the automatic switch gate circuit 6 is electrically connected to the RS232 voltage conversion circuit 3, the RS485/RS422 voltage conversion circuit 4, and the host 9, and includes an output terminal 61 electrically connected to the host 9. A diode 62, a second diode 63, and a resistor 64.

The first diode 62 has a cathode electrically connected to the RS232 voltage conversion circuit 3 to receive the RS232 level adjustment signal, and an anode.

The second diode 63 has a cathode electrically connected to the RS485/RS422 voltage conversion circuit 4 for receiving the RS485/RS422 level adjustment signal, and an anode electrically connected to the first diode 62 and the output end. The anode of 61.

The first diode 62 and the second diode 63 are respectively based on the RS232 level adjustment signal and the RS485/RS422 level adjustment signal. The bit size is switched between the conduction and the non-conduction to transmit the RS232 level adjustment signal and the RS485/RS422 level adjustment signal to the host 9.

The resistor 64 is electrically connected between a power terminal 65 and an anode of the first diode 62.

The NOT circuit 7 is electrically connected to the RS422 voltage conversion circuit 5 and the host 9, receives an RS422 interface output signal output by the host 9, and outputs the corresponding RS422 internal output signal to the RS422 voltage conversion circuit 5. In the present embodiment, the NOT circuit 7 is implemented using an inverter chip, but is not limited thereto.

The control circuit 8 is electrically connected to the RS485/RS422 voltage conversion circuit 4 and the host 9, receives and outputs the control signal according to an RS485 interface output signal output by the host 9 and the RS422 interface output signal to control the RS485/RS422 voltage. Conversion circuit 4.

RS232 communication interface description:

When the user connects the peripheral device using the RS232 communication interface to the RS232 connector 21 and installs the driver, the driver automatically assigns the corresponding I/O address and interrupt number to the peripheral device. In this embodiment, the I/O address is 3E8, and the interrupt number is IRQ11, but is not limited thereto.

At this time, the RS232 interface specification signal is converted into the RS232 level adjustment signal via the RS232 voltage conversion circuit 3, and then transmitted to the host 9 via the first diode 62 of the automatic switch gate circuit 6, and is completed once. Data reception communication.

RS485 communication interface description:

When the user connects the peripheral device using the RS485 communication interface to the RS485/RS422 connector 22 and installs the driver, the driver automatically assigns the corresponding I/O address and interrupt number to the peripheral device. In this embodiment, the I/O address is 3E8, and the interrupt number is IRQ11, but is not limited thereto.

At this time, the signal of the RS485/RS422 interface specification is converted into the RS485/RS422 level adjustment signal via the RS485/RS422 voltage conversion circuit 4, and then transmitted to the second diode 63 through the automatic switch gate circuit 6. The host 9 completes a data reception communication.

When transmitting communication, the host 9 outputs the RS485 interface output signal, and the RS485/RS422 voltage conversion circuit 4 converts the voltage into the RS485 output signal to the RS485/RS422 connector 22 output.

RS422 communication interface description:

When the user connects the peripheral device using the RS422 communication interface to the RS485/RS422 connector 22 and installs the driver, the driver automatically assigns the corresponding I/O address and interrupt number to the peripheral device. In this embodiment, the I/O address is 3E8, and the interrupt number is IRQ11, but is not limited thereto.

At this time, the signal of the RS485/RS422 interface specification is converted into the RS485/RS422 level adjustment signal via the RS485/RS422 voltage conversion circuit 4, and then transmitted to the second diode 63 through the automatic switch gate circuit 6. The host 9 completes a data reception communication.

When transmitting communication, since the RS422 communication interface uses a differential signal, the host 9 outputs the RS422 interface output signal to the NOT gate. The circuit 7 performs the inversion processing to output the signal to the RS422, and then sends the signal to the RS422 voltage conversion circuit 5 to convert the voltage and output the RS422 output signal to the RS485/RS422 connector 22.

It is worth mentioning that, since the driver is used as the active end of the initiation communication, the RS232 connector 21 and the RS485/RS422 connector 22 can be simultaneously connected to different peripheral devices, and the user needs to select RS232. When one of the communication interfaces of RS485 or RS422 is used, only the corresponding software control can be used to switch, and in the same time zone, the user can only select one of the RS232, RS485 or RS422 communication interfaces, that is, the three kinds of communication. The interface is time-sharing, and the user can further develop the application based on the driver, which can better meet various usage requirements.

Through the above description, the advantages of this embodiment can be summarized as follows:

1. By setting the automatic switch gate circuit 6, when the user wants to switch the RS232 or RS485/RS422 communication interface, the switch can be performed only by using the corresponding software, without opening the case as in the prior art. Adjusting the jumper can switch the communication interface, which greatly increases the convenience of use.

2. By using RS485/RS422 voltage conversion circuit 4, RS422 voltage conversion circuit 5, the automatic switch gate circuit 6, the non-gate circuit 7, and the control circuit 8 instead of the RS485/RS422 conversion chip and jumper in the prior art. The device can greatly reduce the component cost. For example, in this embodiment, the motherboard of each serial port automatic switching device can save 2.4 dollars.

Third, the new serial port automatic switching device has a wide range of applications, and can be applied to embedded systems, industrial PCs (IPCs), servers, and point of sales (POS).

In summary, the present invention not only has the effect of automatically switching the communication interface, but also reduces the component cost and has a wide range of applications, so that the purpose of the present invention can be achieved.

However, the above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, that is, the simple equivalent changes and modifications made in accordance with the scope of the present patent application and the contents of the patent specification, All remain within the scope of this new patent.

21‧‧‧RS232 connector

22‧‧‧RS485/RS422 connector

3‧‧‧RS232 voltage conversion circuit

4‧‧‧RS485/RS422 voltage conversion circuit

5‧‧‧RS422 voltage conversion circuit

6‧‧‧Automatic switch gate circuit

7‧‧‧Non-gate circuit

8‧‧‧Control circuit

9‧‧‧Host

Claims (6)

A serial port automatic switching device comprises: an RS232 connector for connecting a device with an RS232 serial communication interface for transmitting an RS232 interface specification signal; an RS485/RS422 connector for connecting a RS485/RS422 a serial communication interface device for transmitting an RS485/RS422 interface specification signal; an RS232 voltage conversion circuit electrically connecting the RS232 connector to receive the RS232 interface specification signal from the RS232 connector, and the RS232 interface The standard signal is voltage-converted to obtain an RS232 level adjustment signal; an RS485/RS422 voltage conversion circuit is electrically connected to the RS485/RS422 connector to receive the RS485/RS422 interface specification signal from the RS485/RS422 connector. And the RS485/RS422 interface specification signal is voltage-converted to obtain an RS485/RS422 level adjustment signal; and an automatic switch gate circuit includes: a first diode having an electrical connection to the RS232 voltage conversion circuit a cathode for receiving the RS232 level adjustment signal, and an anode; a second diode having an electrical connection to the RS485/RS422 voltage conversion circuit Receiving the RS485 / RS422 level Adjusting a cathode of the signal, and an anode electrically connected to the anode of the first diode; the first diode and the second diode are respectively adjusted according to the RS232 level adjustment signal and the RS485/RS422 level The level of the signal is switched between the conduction and the non-conduction to correspond to the RS232 level adjustment signal and the RS485/RS422 level adjustment signal. The serial port automatic switching device of claim 1, wherein the automatic switch gate circuit further comprises: a resistor electrically connected between a power terminal and the anode of the first diode. The serial port automatic switching device of claim 2, wherein the RS485/RS422 voltage conversion circuit further receives an RS485 interface output signal, and performs voltage conversion on the RS485 interface output signal to output a corresponding RS485 output signal to the RS485/RS422 connector. The serial port automatic switching device according to claim 3, further comprising: an RS422 voltage conversion circuit electrically connected to the RS485/RS422 connector; and a non-gate circuit electrically connected to the RS422 voltage conversion circuit to receive an RS422 interface output signal And outputting a corresponding RS422 internal output signal; The RS422 voltage conversion circuit receives the RS422 internal output signal and voltage-converts the RS422 internal output signal to output a corresponding RS422 output signal to the RS485/RS422 connector. The serial port automatic switching device of claim 4, further comprising: a control circuit electrically connected to the RS485/RS422 voltage conversion circuit, the control circuit receiving and outputting a control signal according to the RS485 interface output signal and the RS422 interface output signal; The RS485/RS422 voltage conversion circuit receives and outputs the RS485/RS422 level adjustment signal according to the control signal, and one of the RS485 output signals. The serial port automatic switching device of claim 4, wherein the RS422 voltage conversion circuit is a three-state gate wafer.