KR102211981B1 - Simulator for serial communication - Google Patents

Abstract

The present invention relates to a simulator for serial communication, wherein in electronic devices which are connected to each other and communicate with each other, even if the distance between the respective electronic devices is long, it is possible to easily verify the integrity of the serial communication interface between the corresponding electronic devices to develop or repair the corresponding electronic device more efficiently.

Description

Serial communication simulator {Simulator for serial communication}

The present invention relates to a serial communication simulator.

Different electronic devices are connected and communicated with each other through various methods (wired or wireless). In developing such an electronic device, it is important to check the integrity of the communication interface between different electronic devices. In general, product development is performed after first checking the integrity of the communication interface of the electronic device.

Among these communication methods, in the case of serial communication such as RS422 communication, information on a communication line and signal characteristics of a transceiver are required to design a serial communication transceiver. After designing a serial communication transceiver including a front-end circuit based on this information, it is necessary to verify that the design is appropriate. However, in places with low accessibility such as satellite launch fields, there are not many such verification opportunities, so it is not easy to properly verify design details, and when changing the design of a transceiver, it is difficult to verify the design changes again.

Korean Registered Patent Publication No. 10-2045386 ("Signal simulator for detecting the operation of automobile parts", announced on November 15, 2019)

The present invention was devised to solve the above problems, and an object of the serial communication simulator according to the present invention is, in electronic devices connected to each other to perform communication, even if the distance between the electronic devices is long, The objective is to provide a serial communication simulator capable of developing or repairing a corresponding electronic device more efficiently by making it possible to easily verify the integrity of a serial communication interface of a corresponding electronic device.

In the serial communication simulator according to the present invention for solving the above-described problems, in the serial communication simulator simulating a first electronic device and a second electronic device in which serial communication is performed by being connected in series with each other, the body part, the A first communication unit that is implemented inside the body to simulate the communication module of the first electronic device, and includes a first transmission line and a first receiving line, and is implemented inside the body to provide a communication module of the second electronic device. A second communication unit including a second transmission line and a second reception line, a line connecting the first transmission line and the second reception line, and a line connecting the first transmission line and the second reception line, and the second communication unit A first switch, each positioned on a line connecting a first receiving line, to determine whether the first transmission line and the second receiving line are connected, and whether the second transmission line is connected to the first receiving line, It is located outside the body and determines whether the first transmission line and the second reception line are connected, and an external connection unit that determines whether the second transmission line is connected to the first reception line, and according to the user's manipulation And a control unit for applying an input signal to at least one of the first communication unit and the second communication unit, or turning the first switch on or off, wherein the serial communication simulator includes on/off of the first switch and It characterized in that the inner loop back or the outer loop back is performed according to the connection state of the outer connection part.

In addition, when the first switch is turned on and the external connection unit does not connect the transmission line and the reception line, the control unit transmits a signal to at least one of the first communication unit and the second communication unit, It is characterized in that the inner loopback is performed by receiving a signal corresponding to the signal through another communication unit.

Further, in a state in which the first switch is turned off, the external connection unit connects the first transmission line and the second reception line, and connects the second transmission line and the first reception line, the controller A signal is transmitted to at least one of the first communication unit and the second communication unit, and a signal corresponding to the signal is received by the other communication unit to perform the outer loopback.

A serial communication simulator according to another embodiment of the present invention is a serial communication simulator simulating a first electronic device and a second electronic device that are serially connected to each other to perform serial communication, and is implemented in the body part and the body part. A first communication unit including a first transmission line and a first receiving line, and a first communication unit including a first transmission line and a first receiving line to simulate the communication module of the second electronic device, A second communication unit including a transmission line and a second reception line, a line located inside the body, and connecting the first transmission line and the second reception line, and the second transmission line and the first reception line. A first switch, the first transmission line, respectively located on a connecting line to determine whether the first transmission line and the second reception line are connected, and whether the second transmission line and the first reception line are connected , The first receiving line, the second transmitting line and a second switch positioned on the second receiving line, and an input signal to at least one of the first communication unit and the second communication unit according to a user's manipulation. Including a control unit for applying or turning on or off the first switch or the second switch, and the two different serial communication simulators have their respective transmission lines and reception lines connected to each other, and are included in each of the serial communication simulators. It characterized in that the outer loop back is performed according to the on/off state of the first switch and the second switch.

In addition, the second switch located on the first transmission line and the second transmission line is located earlier than the line on which the first switch is located, and the second switch located on the first and second reception lines. The second switch is characterized in that it is located at a rear end of the line where the first switch is located.

In addition, the first switch included in the first serial communication simulator is turned off, the second switch is turned on, the first switch included in the second serial communication simulator is turned on, and the second switch is turned off. The control unit included in the first serial communication simulator transmits a signal to one of the first communication unit and the second communication unit included in the first serial communication simulator, and corresponds to the signal to the other communication unit. A signal is received and the outer loopback is performed.

In addition, each of the first communication unit and the second communication unit may include a transmission differential amplifier; It characterized in that it further comprises a receiving differential amplifier and a resistor connected in series to each of the transmitting differential amplifier and the receiving differential amplifier.

In addition, the resistance is characterized in that the variable resistance.

In addition, at least one communication unit of the first communication unit and the second communication unit further comprises a terminating resistor unit including a first resistor connected in series to a receiving line connected to the receiving differential amplifier of the corresponding communication unit. .

In addition, the terminating resistor may further include a second resistor connected in parallel with the receiving line between the first resistor and the receiving differential amplifier.

Further, at least one of the first resistor and the second resistor may be a variable resistor.

In addition, the single receiving differential amplifier is connected to two receiving lines, and the terminating resistor unit is a first line connecting the two receiving lines to a front end of the first resistor, and connected in series on the first line. And a third resistor connected in series with the third resistor on the first line, and a third switch connected in parallel to both ends of the capacitor.

According to the serial communication simulator according to the present invention as described above, the communication modules of the first electronic device and the second electronic device are simulated inside a single serial communication simulator, and each communication module is connected from the inside/outside of the body. By performing the inner loopback and the outer loopback by performing the communication interface integrity of the simulator itself, there is an effect of verifying the integrity of the communication interface of the first electronic device, the second electronic device, and the communication line.

1 is a schematic diagram of a satellite and a control room to be simulated in the serial communication simulator of the present invention,
2 is a circuit diagram of a serial communication simulator according to the first embodiment of the present invention,
3 is a circuit diagram when the serial communication simulator according to the first embodiment of the present invention performs an inner loopback,
4 is a circuit diagram when the serial communication simulator according to the first embodiment of the present invention performs an external loopback,
5 is a circuit diagram of the serial communication simulator according to the second embodiment of the present invention when performing an external loopback.

The drawings introduced below are provided as examples in order to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. At this time, unless there are other definitions in the technical terms and scientific terms used, they have the meanings commonly understood by those of ordinary skill in the technical field to which this invention belongs, and the gist of the present invention in the following description and accompanying drawings Descriptions of known functions and configurations that may be unnecessarily obscure will be omitted.

Before describing preferred embodiments of a serial communication simulator according to various embodiments of the present invention, an electronic device to be simulated of a connection simulator according to the present invention will be described first.

Objects to be simulated in the serial communication simulator according to various embodiments of the present invention described below are a first electronic device and a second electronic device connected in series to each other to transmit and receive signals. The first electronic device and the second electronic device may be various types of devices that are connected to each other to perform serial communication.

1 illustrates a satellite 10 and a control room 20 as targets to be simulated in a serial communication simulator according to various embodiments of the present invention, which will be described below.

The satellite 10 and the control room 20 shown in FIG. 1 may be the first electronic device and the second electronic device described above. As shown in FIG. 1, the satellite 10 is generally located inside the top of the launch vehicle 30. Therefore, in order for the satellite 10 and the control room 20 to communicate with each other before the launch vehicle 30 is launched, a communication line connecting the satellite 10 and the control room 20 is required. The communication line may be formed inside the launch vehicle, as shown in FIG. 1, while connecting the satellite 10 and the control room 20, an external transmission line and an external transmission line formed through the inside of the launch vehicle 30 ( 50) may be the corresponding communication line.

The external transmission line 40 and the external reception line 50 illustrated in FIG. 1 may be one-way lines through which signals are transmitted only to one side. That is, the signal transmitted from the control room 20 is transmitted to the satellite 10 through the external transmission line 40, and the signal transmitted from the satellite 10 is transmitted to the control room 20 through the external reception line 50. Can be.

As shown in FIG. 1, considering the situation when the projectile 30 is launched, the control room 20 is generally located underground. Considering the relative position difference between the satellite 10 and the control room 20, the external transmission line 40 and the external reception line 50 must be at least 100m or more. In order to verify after designing a newly designed serial communication transceiver, the serial communication transceiver needs to be installed in the satellite 10 and the control room 20, respectively, and then send a signal from either side. The satellites located at both ends of the external transmission line 40 and the external reception line 50 have to be installed respectively in the control room 20 and at the same time, at the same time, at least two people have to be located in the satellite 10 and the control room 20. 10) There was a rather difficult problem to check the integrity of the communication interface between the launch vehicle 30.

Hereinafter, a serial communication simulator according to various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First embodiment]

2 shows a circuit diagram of a serial communication simulator according to the first embodiment of the present invention.

As shown in FIG. 2, the serial communication simulator 1000 according to the first embodiment of the present invention includes a first communication unit 100, a second communication unit 200, a first switch 300, and an external connection unit 400. ) And a control unit (not shown).

The first communication unit 100 simulates the communication module of the first electronic device described above, that is, the satellite 10. As described above, the communication module of the satellite 10 uses TX/RX communication in which transmission and reception lines are separated, and thus may include a first transmission line and a first reception line. As shown in FIG. 2, a first transmission differential amplifier 610 and a first reception differential amplifier 620 are positioned at a transmission terminal (TX) and a reception terminal (RX) of the first communication unit 100, respectively.

A differential amplifier is an element that amplifies a signal in proportion to the difference between two input signals. More specifically, the first transmission differential amplifier 610 separates and amplifies the transmitted signal into two signals, and the 1TX+ line 101 and the 1TX-line 102 included in the first transmission line each signal. Divide by and send. The first receiving differential amplifier 620 receives signals input to the first RX+ line 103 and the first RX-line 104, respectively, and communicates using a difference in magnitude of each signal. The use of such a differential amplifier has a feature that is less affected by noise and interference than a single amplifier (one-stage amplifier), does not require a coupling capacitor and a bypass capacitor, and is easy to manufacture in an integrated circuit. In the case of the first transmission differential amplifier 610, since it is a device through which signals are input and transmitted, it can be referred to as a driver chip. In the case of the first receiving differential amplifier 620, a receiver is a device that receives and outputs signals. It can be called a receiver chip.

The second communication unit 200 simulates the second electronic device described above, that is, the communication module of the control room 20. The communication module of the control room 20 also includes a second transmission line and a second reception line, and a second transmission line, because it uses TX/RX communication in which the transmission and reception lines are separated, like the communication module of the satellite 10. Also, like the first transmission line, it includes two TX lines, that is, the second TX+ line 201 and the second TX-line 202, and the second reception line also includes two RX lines, that is, the second RX+ line, like the first reception line. A line 201 and a second RX-line 202 may be included. In addition, as shown in FIG. 2, a second transmission differential amplifier 710 and a second reception differential amplifier 720 are respectively positioned at the transmission terminal TX and the reception terminal RX of the second communication unit 100.

The first communication unit 100 and the second communication unit 200 may be installed together in a type of body unit (not shown), and the user carries the body unit, and a communication interface between the first electronic device and the second electronic device to be simulated The soundness can be verified.

As shown in FIG. 2, the first switch 300 is located inside the body part, and a line connecting the first transmission line and the second receiving line, and a line connecting the second transmission line and the first receiving line They are located on each of the images, and determine whether the first transmission line and the second reception line are connected, and whether the second transmission line and the first reception line are connected. As described above, the first transmission line is the first TX+ line 101 and the second TX-line 102, the first receiving line is the first RX+ line 103 and the first RX-line 104, the second transmission Since the line includes the second TX+ line 201 and the second TX-line 202, and the second receiving line includes the second RX+ line 203 and the second RX-line 204, the first switch 300 is A line connecting the first TX+ line 101 and the second RX+ line 203, a line connecting the first TX-line 102 and the second RX-line 204, the first RX+ line 103 and the second TX+ line 201 ) May be disposed on a line connecting the first RX-line 104 and the second TX-line 202, respectively. For convenience of explanation, in the serial communication simulator according to the first embodiment of the present invention shown in FIG. 2, the first switch 300 including all switches disposed on each of the four lines is referred to as the first switch 300. All four included switches are simultaneously closed (closed) open (open) and turned on or off to determine whether the first transmission line and the second reception line are connected, and whether the second transmission line and the first reception line are connected. I can.

As shown in FIG. 2, the external connection part 400 is located outside the body part, determines whether the first transmission line and the second reception line are connected from the outside of the body part, and determines whether the second transmission line and the first reception line are connected. Determine whether or not to connect. More specifically, the external connection unit 400 is a type of jumper and connects two lines in series so that a signal transmitted from one of the two lines is transmitted to the other line. That is, the external reception line 40 and the external transmission line 50 shown in FIG. 2 are connected in series through the external connection unit 400, so that the first communication unit 100 and the second communication unit 200 communicate with each other. Connect as possible.

According to the present invention, the integrity of the communication interface may be verified in one place by using the external connection unit 400 and the body unit in which the first communication unit 100 and the second communication unit 200 are implemented.

The control unit applies an input signal to any one of the first communication unit 100 and the second communication unit 200 according to the user's manipulation, or the input signal to both the first communication unit 100 and the second communication unit 200. Can be approved. In addition to this, the control unit closes, opens, turns on or off the first switch 100 according to the user's manipulation, so that the serial communication simulator according to the first embodiment of the present invention performs an inner loopback or an outer loopback. Do it.

As shown in Figure 2, the second switch 610 is formed in series on the first TX+ line 101, the first TX-line 102, the first RX+ line 103, and the first RX-line 104. have. In more detail, in the first TX+ line 101 and the first TX-line 102, the second switch 610 is located in front of the line to which the first switch 300 is connected (the direction in which the signal arrives first), and the first RX+ line In 103 and the first RX-line 104, the second switch 610 is positioned at a rear end (in the direction in which the signal arrives later) than the line to which the first switch 300 is connected. The second switch 610 can always be kept closed in the operation of this embodiment using a single serial communication simulator. Accordingly, the second switch 610 will be described in detail in another embodiment using two serial communication simulators in which the second switch 610 is used.

As described above, since TX/RX communication is used in the serial communication simulator according to the first embodiment of the present invention, the first TX+ line 101 and the first TX-line 102 formed in the first communication unit 100 , A plurality of resistors may be included in the first RX+ line 103 and the first RX-line 104. 2, the first transmission differential amplifier 610 has a first TX+ line 101 and a first TX-line 102 connected to each other, the first TX+ line 101 and the first TX-line ( A series resistor 621 may be connected in series to 102). The series resistance 621 may be a variable resistance, which is the value of the series resistance 621 according to the characteristic impedance of the transmission line to which the serial communication simulator according to the first embodiment of the present invention is applied. This is to prevent signal reflection from occurring. The terminating resistor unit composed of a plurality of resistors formed in the first RX+ line 103 and the first RX-line 104 included in the first communication unit 100 is also for preventing the characteristics of the communication line and signal reflection. .

The terminating resistors formed in the first RX+ line 103 and the first RX-line 104 will be described in more detail. The terminating resistor unit has a first resistor 622 connected in series to each of the first RX+ line 103 and the first RX-line 104 connected to the front end of the first receiving differential amplifier 620, and the first resistor 622 and Second resistors 623 and 624 may be connected in parallel between the first receiving differential amplifier 620. The two second resistors 623 and 624 may be pull-up resistors and pull-down resistors, respectively. The second resistors 623 and 624 are present to have a value of 1 or 0 at the receiving end (RX) when the transmitting end (TX) does not transmit a signal. When the transmitting end (TX) does not transmit a signal, the The 1RX+ line 103 has a VCC voltage, and the first RX-line 104 is connected to the ground to have 0V, so that the voltage difference can be clear.

The termination resistor may include a third resistor 625 and a capacitor 626 shown in FIG. 2. A line connecting the first RX+ line 103 and the first RX-line 104 to each other is formed at the front end of the first receiving differential amplifier 620, and the third resistor 625 and the capacitor 626 are in series with the corresponding line. Leads to A third switch 627 is formed in parallel at both ends of the capacitor 626. When the third switch 627 is closed, it becomes a circuit equivalent to no capacitor 626 in the corresponding line, and the third switch 627 When) is opened, it becomes a circuit equivalent to that of the capacitor 626 in the corresponding line. That is, the user can determine whether or not to add the capacitor 626 by closing or opening the third switch 627, so it can be designed according to the characteristics of the communication line, and the case where the third switch 627 is closed is called parallel termination. And, the case where the third switch 627 is opened is referred to as AC Termination.

Since the second communication unit 200 has the same configuration as the first communication unit 100, the series resistance 721, the first resistance 722, and the second resistance 723 are located at a position corresponding to the first communication unit 100. 724), a third resistor 725, a third switch 726, and a third switch 727 may be included.

[Example 1-Inner Loop Back]

3 is a circuit diagram when the serial communication simulator according to the first embodiment of the present invention performs an inner loopback.

The inner loopback is used to check whether the simulator itself is operating normally before attempting to verify the integrity of the communication interface using the serial communication simulator according to various embodiments of the present invention. Therefore, when performing the inner loopback, the transmitted/received signal is transmitted only inside the body part of the serial communication simulator according to the first embodiment of the present invention, and the part where the signal is transmitted in FIG. 3 is displayed in bolder than other parts. I did.

As shown in FIG. 3, when the inner loopback is performed in the serial communication simulator according to the first embodiment of the present invention, the first switch 300 is closed and turned on, and the second switches 510 and 520 are also Being closed, but the external connection 400 is not used. Therefore, the signal input through the transmitting end (TX) is the first transmission differential amplifier 610/1 TX + line 101 and the 1 TX-line 102 / the first switch 300/2 RX + line 203 and the first 2RX-line 204/second receiving differential amplifier 720, or received in order, or second transmitting differential amplifier 710/second TX+ line 201 and second TX-line 202/first switch 300 )/The first RX+ line 103 and the first RX-line 104/first receiving differential amplifier 620 are received in this order, so that the health of the communication interface of the body unit itself can be verified.

[Example 1-Outer Loop Back]

4 is a circuit diagram of the serial communication simulator according to the first embodiment of the present invention when performing an external loopback.

The outer loopback is intended to verify the integrity of the communication line, the communication interface of the first electronic device and the second electronic device by using the serial communication simulator according to various embodiments of the present invention. Therefore, when performing the outer loopback, the transmitted/received signal is transmitted from the body part of the serial communication simulator according to the first embodiment of the present invention to the outside and then received back to the body part.

As shown in Fig. 4, when the outer loopback is performed in the serial communication simulator according to the first embodiment of the present invention, the first switch 300 is open and off, and the second switches 510 and 520 are It is closed (closed) on, but the external connection unit 400 connects the first transmission line of the first communication unit 100 and the second reception line of the second communication unit 200, and the first reception of the first communication unit 100 The line and the second transmission line of the second communication unit 200 are connected. Therefore, the signal input through the transmission terminal (TX) is the first transmission differential amplifier 610/1 TX + line 101 and the 1 TX-line 102 / external transmission line 40 / external connection unit 400 / external reception The line 50 / second RX+ line 203 and the second RX-line 204 / second receiving differential amplifier 720 are received in order, or the second transmission differential amplifier 710 / second TX + line 201 and 2nd TX-line 202/external receiving line 50/external connection part 400/external transmission line 40/first RX+ line 103 and first RX-line 104/first receiving differential amplifier 620 ) Are sequentially received, and the integrity of the communication interface of the external transmission line, the external reception line, and the first electronic device and the second electronic device can be verified.

[Second Example]

5 shows a circuit diagram of a serial communication simulator according to a second embodiment of the present invention.

As shown in Fig. 5, the serial communication simulator according to the second embodiment of the present invention uses two serial communication simulators, and for convenience, the first serial communication simulator 1000 and the second serial communication simulator 2000 are used. Call.

The serial communication simulator according to the second embodiment of the present invention is different from that of the configurations included in the serial communication simulator according to the first embodiment described above in that the two serial communication simulators are used together while the external connection is excluded. In this embodiment, when the first serial communication simulator 1000 performs an outer loopback, the second serial communication simulator 2000 is used.

As shown in FIG. 5, the first serial communication simulator 1000 and the second serial communication simulator 2000 are each of the first TX+ line 101, the first TX-line 102, the first RX+ line 103, and The first RX-line 104, the second TX+ line 201, the second TX-line 202, the second RX+ line 203, and the second RX-line 204 are connected to each other. In more detail, the first TX+ line 101 and the first TX-line 102 of the first serial communication simulator 1000 are connected to the first RX+ line and the first RX-line of the second serial communication simulator 2000, respectively. , The first RX+ line 103 and the first RX-line 104 of the first serial communication simulator 1000 are connected to the first TX+ line and the first TX-line of the second serial communication simulator 2000, respectively. In addition, the second TX+ line 201 and the second TX-line 202 of the first serial communication simulator 1000 are connected to the second RX+ line and the second RX-line of the second serial communication simulator 2000, respectively, and are connected to the second RX+ line. The line 203 and the second RX-line 204 are connected to the second TX+ line and the second TX-line of the second serial communication simulator 2000, respectively. The reason why the first serial communication simulator 1000 and the second serial communication simulator 2000 are connected as described above with FIG. 5 is, in verifying the integrity of the communication interface of the first serial communication simulator 1000, the TX line is This is because only signal transmission is possible, and only signal reception is possible on the RX line.

As shown in FIG. 5, in order to perform the outer loopback of the first serial communication simulator 1000 in this embodiment, the first switch 301 of the first serial communication simulator 1000 is opened and turned off. The second switches 511 and 521 are closed and turned on, the first switch 302 of the second serial communication simulator 2000 is closed and the second switches 512 and 522 are It is open and off. In this case, the signal transmitted through the transmitting end (TX) of the first serial communication simulator 1000 is output from the first serial communication simulator 1000, passes through the second serial communication simulator 2000, and then passes through the second serial communication simulator 2000. Lines received by the communication simulator 1000 and through which signals are transmitted and received are indicated in bold in FIG. 5. That is, in this embodiment, by controlling the first switch and the second switch included in the two serial communication simulators connected to each other, any one serial communication simulator is connected to the external transmission line 40 shown in FIGS. The integrity of the communication interface of the first electronic device simulated in the first serial communication simulator 1000 may be verified by performing an external loopback without using the connection unit 400 and the external reception line 50.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

10: satellite 20: control room
30: projectile 40: external transmission line
50: external receiving line 100: first communication unit
101: first TX+ line 102: first TX-line
103: first RX+ line 104: first RX-line
200: 2nd communication unit 201: 2nd TX+ line
202: 2ndTX-line 203: 2nd RX+ line
204: second RX-line 300, 301, 302: first switch
400: external connection
510, 511, 512, 520, 521, 522: second switch
610: first transmitting differential amplifier 620: first receiving differential amplifier
621, 721: series resistance 622, 722: first resistance
623, 624, 723, 724: second resistance 625, 725: third resistance
626, 726: capacitor 627, 727: third switch
710: second transmission differential amplifier 720: second reception differential amplifier
1000: first serial communication simulator 2000: second serial communication simulator

Claims (12)

delete delete delete In a serial communication simulator simulating a first electronic device and a second electronic device connected in series to perform serial communication,
Body part;
A first communication unit implemented inside the body to simulate a communication module of the first electronic device, the first communication unit including a first transmission line and a first reception line;
A second communication unit implemented inside the body to simulate a communication module of the second electronic device, and including a second transmission line and a second reception line;
It is located inside the body, and is located on a line connecting the first transmission line and the second receiving line, and a line connecting the second transmission line and the first receiving line, respectively, and the first transmission line and A first switch that determines whether the second transmission line is connected and whether the second transmission line is connected to the first reception line;
A second switch positioned on the first transmission line, the first reception line, the second transmission line, and the second reception line; And
A control unit for applying an input signal to at least one of the first communication unit and the second communication unit or turning on or off the first switch or the second switch according to a user's manipulation;
Including,
In the two different serial communication simulators, respective transmission lines and reception lines are connected to each other,
Performing an external loopback according to the on/off state of the first switch and the second switch included in each of the serial communication simulator,
The second switch located on the first transmission line and the second transmission line is located in front of the line where the first switch is located,
The serial communication simulator, wherein the second switch positioned on the first receiving line and the second receiving line is positioned at a rear end of the line where the first switch is positioned.
delete The method of claim 4,
The first switch included in the first serial communication simulator is turned off, the second switch is turned on, and the first switch included in the second serial communication simulator is turned on, and the second switch is turned off. The control unit included in the first serial communication simulator transmits a signal to one of the first communication unit and the second communication unit included in the first serial communication simulator, and transmits a signal corresponding to the signal to the other communication unit. A serial communication simulator, characterized in that receiving and performing the outer loopback.
The method of claim 4,
Each of the first communication unit and the second communication unit may include a transmission differential amplifier; Receiving differential amplifier; And
A resistor connected in series to each of the transmitting differential amplifier and the receiving differential amplifier;
Serial communication simulator, characterized in that it further comprises.
The method of claim 7,
Serial communication simulator, characterized in that the resistance is a variable resistance.
The method of claim 7,
At least one of the first communication unit and the second communication unit includes: a terminating resistor unit including a first resistor connected in series to a receiving line connected to the receiving differential amplifier of the corresponding communication unit;
Serial communication simulator, characterized in that it further comprises.
The method of claim 9,
The terminating resistor unit may include a second resistor connected in parallel with the receiving line between the first resistor and the receiving differential amplifier;
Serial communication simulator, characterized in that it further comprises.
The method of claim 10,
At least one of the first resistance and the second resistance is a serial communication simulator, characterized in that the variable resistance.
The method of claim 9,
The single receiving differential amplifier is connected to two receiving lines,
The termination resistor unit,
A first line connecting the two receiving lines to a front end of the first resistance;
A third resistor connected in series on the first line;
A capacitor connected in series with the third resistor on the first line; And
A third switch connected in parallel to both ends of the capacitor;
Serial communication simulator comprising a.

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