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BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW BusVIEW

Slave

s o f t w a r e w i t h r e l i s h

Copyright ©1994-96 SEG division of Soogatech CorporationAll rights reserved.

BusVIEW Slave manual version 1.0.1 revised 11/96.

s o f t w a r e w i t h r e l i s h

www.softwarewithrelish.comS E G . 126A Main St . Second Floor . Watertown, MA 02142 . (617) 924-6664

Product names mentioned in this manual are trademarks or registered trademarks of theirmanufacturers. BusVIEW Slave, the BusVIEW logo, SEG and the hot dog logo aretrademarks of Soogatech Corporation.

Special thanks to Morten Andresen, CARDIAC as, Norway, who first suggested and testedthis product on a North Sea oil rig.

Important WarningBecause of the variety of uses of this product, and the impossibility of our anticipating everyuse, those responsible for using and applying this product must satisfy themselves that it isappropriate and acceptable for their application. That responsibility includes using thisproduct in accordance with all sound engineering, programming and safety practices,particularly in accordance with the use of Modbus devices as recommended by theirmanufacturers.

The diagrams and layout examples shown in this manual are presented solely to illustratethe text of the manual. Soogatech Corporation (SEG) assumes no responsibility for actualuses based on illustrated uses or applications.

LicenseYou have a non-exclusive license to use the BusVIEW Slave software. You may use thisproduct on one computer at a time. For backup purposes only, you may copy BusVIEWSlave software to other disks which you must retain in your possession and control. Youmay not copy BusVIEW Slave software to any other computer by any means for any otherpurpose.

The BusVIEW Slave software, related documentation and their look and feel arecopyrighted. You may not modify, disassemble or translate BusVIEW software or relateddocumentation without the written consent of SEG.

WarrantySoogatech Corporation (SEG) warrants both this manual and the BusVIEW Slave programdisks to be free from defects for one year from the date of purchase. If, during this warrantyperiod, you find that this manual or the BusVIEW Slave disks contain physical defects,return the defective item along with proof of purchase and a description of the defect. Youwill receive a replacement at no charge.

SEG makes no warranty or representation, express or implied, with respect to this software,its performance or its fitness for a particular purpose. As a result, the software is sold “as is”and you, the purchaser, assume the entire risk as to quality and performance. In no eventshall SEG be liable for direct or indirect, special, incidental or consequential damagesresulting from any defect in the software or its documentation. Such damages include butare not limited to loss of profit, opportunity, programs or data. In no case will SEG be liablefor damages due to action or inaction of governments or quasi-governments, acts of riot,civil unrest, natural disasters or force majeure.

This warranty excludes all other warranties, oral or written, express or implied.

The exclusion of implied warranties is not permitted in some states. The above exclusionsmay not apply to you. This warranty provides you with specific legal rights. You may haveother rights that vary from state to state.

Intended AudienceThis manual assumes you are familiar with basic operations such as pointing and clicking,launching an application and moving files. Because BusVIEW Slave works with LabVIEWsoftware and Modbus hardware, familiarity with LabVIEW and Modbus controllers isassumed. If you have just purchased LabVIEW or Modbus controllers, you shouldfamiliarize yourself with those products before you attempt to install or use BusVIEW Slave.

TABLE OF CONTENTS

1 Overview.................................................................................................. 1

1.1 What is BusVIEW Slave?.............................................................................................. 11.2 Requirements ................................................................................................................ 11.3 If You Need Help .......................................................................................................... 1

2 Hardware Installation................................................................................ 2

3 Software Installation.................................................................................. 3

4 Using BusVIEW Slave ............................................................................... 4

4.1 BusVIEW Slave VIs in a Nutshell................................................................................ 44.2 Tutorial........................................................................................................................... 6

5 VI Reference............................................................................................. 12BV Slave Init References...................................................................................... 12BV Slave Init Comm ............................................................................................. 12BV Slave Process Messages ................................................................................ 13BV Slave Read 0X.................................................................................................. 14BV Slave Write 0X ................................................................................................ 14BV Slave Read 0Xs................................................................................................ 14BV Slave Write 0Xs .............................................................................................. 14BV Slave Read 1X.................................................................................................. 15BV Slave Write 1X ................................................................................................ 15BV Slave Read 1Xs................................................................................................ 15BV Slave Write 1Xs .............................................................................................. 16BV Slave Read 3X.................................................................................................. 16BV Slave Write 3X ................................................................................................ 16BV Slave Read 3Xs................................................................................................ 16BV Slave Write 3Xs .............................................................................................. 17BV Slave Read 4X.................................................................................................. 17BV Slave Write 4X ................................................................................................ 17BV Slave Read 4Xs................................................................................................ 17BV Slave Write 4Xs .............................................................................................. 18

6 Cable Pinouts ........................................................................................... 19

6.1 PC DB-25 to Modicon DB-9 ......................................................................................... 196.2 PC DB-25 to Modicon DB-25 ....................................................................................... 196.3 PC DB-25 to Modicon RJ45 .......................................................................................... 206.4 PC DB-9 to Modicon DB-9 ........................................................................................... 206.5 PC DB-9 to Modicon DB-25 ......................................................................................... 216.6 PC DB-9 to Modicon RJ45 ............................................................................................ 21

BusVIEW™ Slave User’s Guide

1

1 OVERVIEW

1.1 What is BusVIEW Slave?

The BusVIEW™ Slave system allows National Instruments’ LabVIEW software to respondto queries from Modbus master devices.

You use BusVIEW Slave to create a virtual controller that resides in a LabVIEW globalvariable. You can read and write to virtual controller with special VIs.

Other VIs are used to service requests from a Modbus master, so the Modbus masterbelieves it is communicating with a Modbus device, although it is actually communicating toLabVIEW and its virtual controller.

1.2 Requirements

You can use BusVIEW Slave on any machine that can run LabVIEW 3 software. Refer toNational Instruments’ documentation for recommended computer specifications.

You must have LabVIEW 3.0 or later to run BusVIEW Slave. You should be familiar withLabVIEW before attempting to install or use BusVIEW Slave.

You will need to wire an interface cable to connect your computer serial port to the Modbusdevice. See Section 6 for cable pin-outs.

1.3 If You Need Help

BusVIEW Slave technical support is available from 10 a.m. to 6 p.m., Eastern time. Call(617) 924-6664 and ask for BusVIEW Slave Technical Support.

Our website is http: //www.softwarewithrelish.com

You may also FAX diagrams and technical questions to (617) 924-3402.


2

2 HARDWARE INSTALLATIONWARNING!

When installing or removing interface cables, always power down theModbus device and the computer. Otherwise, you may damage yourequipment.

You connect your computer to Modbus devices with an interface cable. One end of the cableconnects to a serial port on your computer. The other end connects to the Modbus port of aModbus device.

NOTE

You must set the Modbus device’s port to use the serial lineconfiguration, framing method and slave address you desire. Thesevalues must match those used by BV Slave Init Comm VI.

Of course, BusVIEW Slave will not work properly unless the Modbus equipment is firstinstalled correctly. To minimize problems, try to verify your Modbus configuration beforeattempting to install BusVIEW Slave.


3

3 SOFTWARE INSTALLATIONYou must already have installed LabVIEW 3 before you can install BusVIEW Slave.

Insert the BusVIEW Slave disk into a 3.5-in disk drive.

If you are installing BusVIEW Slave on a Macintosh, drag the file BVSLAVE.LLB intoLabVIEW’s vi.lib folder.

If you are installing BusVIEW Slave on a PC, copy the directory BVSLAVE.LIB and itscontents into the directory that contains the LabVIEW software.

Use the DOS command

xcopy x: y:\labviewdir /s

where x is the designation for the 3.5-in disk driver, y is the designation for the hard drivercontaining the LabVIEW directory and labviewdir the directory where LabVIEW is installed


4

4 USING BUSVIEW SLAVE

4.1 BusVIEW Slave VIs in a Nutshell

To use BusVIEW slave you must:

1) Use the BV Slave Init References VI to create the virtual controller.

2) Use the BV Slave Init Comm VI to describe the communication link between LabVIEWand your Modbus Master device.

When the virtual controller is is intialized by BV Slave Init References, all of its datalocations are set to zero. To changes these values, you must use Read and Write referenceVIs. These VIs allow you to read and write to discrete outputs(0X), discrete inputs(1X),input registers(3X) and holding registers(4X).

The LabVIEW application must call BV Slave Process Messages frequently to allowMaster queries to be serviced. Master queries are buffered at the serial port until BV SlaveProcess Messages reads them. BusVIEW Slave will process the following Modbuscommands:

CommandCode Name

1 Read Coil Status2 Read Input Status3 Read Holding Registers4 Read Input Registers5 Force Single Coil6 Preset Single Register15 Force Multiple Coils16 Preset Multiple Registers23 Read/Write Multiple Registers

The device sending Modbus master queries expects to receive a response within a specifictimeout period. You may need to adjust this timeout period on the Modbus master device ifyou do not call BV Slave Process Messages frequently enough.


5

You access the BusVIEW Slave VIs from the Functions menu when you are editing aLabVIEW diagram.


6

4.2 Tutorial

NOTE

The following tutorial will give you a quick introduction to BusVIEWSlave. You need to be familiar with LabVIEW programming to followthis tutorial. If you are new to LabVIEW, first follow the LabVIEWtutorials provided with National Instruments documentation.

You can find the VIs described in this tutorial in the BVSDEMO.LLBlibrary on the BusVIEW Slave distribution disk.

Consider a Modbus network composed of a master device and a LabVIEW application usingBusVIEW Slave to implement a Modbus virtual controller. The master device updatesdiscrete outputs 1 to 8 and holding registers 1 to 3 in the virtual controller and the LabVIEWapplication displays them on the screen. The LabVIEW application updates discrete inputs 1to 8 and input registers 1, 4 and 10 in the virtual controller which can be read by the masterdevice.


7

How does BusVIEW Slave Example.vi create and maintain the virtual controller? Here isthe diagram:

2

3

4

5

6

1

Create Modbus Slave Device.vi (1) is called to create the controller and define serialcommunications. If the controller is created without error the application executes until the

button on the front panel is clicked. BV Slave Process Messages.vi (2) checks tosee if the Modbus master device has sent a message and replies if it has.

Get Discrete Output Values.vi (3) and Get Holding Register Values.vi (5) update theDiscrete Outputs and Holding Registers indicators on the front panel with the latestinformation in the virtual controller. BV Slave Process Messages.vi (2) updates thevirtual controller with new information from the master device.


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Set Discrete Input Values.vi (4) and Set Input Register Values.vi (6) update the virtualcontroller with the Discrete Inputs and Input Registers controls on the front panel. BVSlave Process Messages.vi (2) sends this information to the master device if it requests it.

How does Create Modbus Slave Device.vi create the controller and define the serialcommunication? Let’s look at its diagram:

1

2

BV Slave Init Comm.vi (1) establishes serial communications and initializes the serialport using the parameters specified by the eight inputs. The first six inputs are the same asthose used by the LabVIEW Serial Port Init VI. The RTU framing and Slave Address arespecial to BusVIEW Slave.

BV Slave Init References.vi (2) creates the controller containing the number of discreteand register values specified by the four inputs. The controller in our example will haveeight discrete outputs, eight discrete inputs, ten input registers and five holding registers.

Once BV Slave Init References.vi and BV Slave Init Comm.vi have been executedBusVIEW Slave is capable of responding to Modbus master device requests sent to theSlave Address passed to the BV Slave Init Comm.vi.


9

Note that we create the device only once in our master diagram (page 7). Since BV SlaveInit References.vi zeros all the controller values, it is important to call it only once.

How does Get Discrete Output Values.vi obtain the state of the discrete outputs? Here isthe diagram:

1 23 4

BV Slave Read 0Xs.vi (1) reads one byte of discrete output data starting at byte zero.Discrete values are packed eight per byte so the first byte of data contains the state of thefirst eight discrete outputs. BV Slave Read 0Xs.vi returns an array of bytes. The firstelement, and only element in this case, is extracted (2), and converted into a boolean arraycontaining eight elements(3). The resulting boolean array is converted into a cluster (4) andreturned to the caller.


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How does Get Holding Register Values.vi obtain register values?

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BV Slave Read 4Xs.vi (1) reads three holding registers starting at holding register 0. Theresulting array is converted into a cluster (2) and returned to the caller.

How does Set Discrete Input Values.vi modify the state of the controller’s discreteinputs?

21 3 4

The caller’s cluster of booleans is converted into a boolean array(1). The array is thenconverted into a number(2) and cast into a unsigned byte. The resulting value is convertedinto a single element array (3) and passed to the BV Slave Write 1Xs.vi (4). BV SlaveWrite 1Xs.vi writes one byte of discrete input data starting at byte zero. Discrete values are


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packed eight per byte so the first byte of data contains the state of the first eight discreteinputs.

How does Set Input Register Values.vi modify the contents of the controller’s inputregisters?

2

1

The caller’s cluster of input registers is converted into three separate input registervalues(1). The values are passed to separate calls of BV Slave Write 3Xs.vi (2). Each callto BV Slave Write 3Xs.vi specifies a different location in the controller’s data table.


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5 VI REFERENCEEach BusVIEW Slave VI is described with a graphic summary of inputs (left) and outputs(right), followed by a description and usage notes. The graphic is similar to the picturedisplayed in the LabVIEW Help Window when you place the wiring tool over a VI in yourdiagram.

BV Slave Init References

Initializes the virtual controller. Discrete values are packed 8 to a byte. If you specifyNumber of Discrete Outputs as 160 then 20 bytes of memory will be used. Registers arestored as unsigned 16 bit values.

All values are set to zero when the virtual controller is initialized.

BV Slave Process Messages will not be able to process queries from the master if the virtualcontroller is not initialized.

BV Slave Init Comm

Initializes the communication parameters used by BV Slave Process Messages. Portnumber, baud rate, data bits, stop bits, parity and buffer size are passed directly toLabVIEW’s serial port VIs. Refer to LabVIEW’s documentation on valid values for theseparameters.

ASCII/RTU specifies the framing method used by BV Slave Process Messages. IfASCII/RTU is FALSE the ASCII framing is used. If ASCII/RTU is TRUE then RTUframing is used. Refer to you Modbus master documentation to determine which framingmethod should be used.


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Local Slave Address establishes the network address. BV Slave Process Messages willonly respond to queries matching this address. If a query is received with another address itis ignored.

BV Slave Process Messages

Determines if incoming serial data is a valid Modbus request addressed to this networkaddress. If the request is valid the VI responds with the appropriate reply.

BV Slave Process Messages will respond to Modbus commands:

CommandCode Name

1 Read Coil Status2 Read Input Status3 Read Holding Registers4 Read Input Registers5 Force Single Coil6 Preset Single Register15 Force Multiple Coils16 Preset Multiple Registers

Other Modbus commands result in illegal function code responses. If a valid commandattempts to read or write data beyond the range of the virtual controller BusVIEW respondswith illegal data address exception code.

The LabVIEW application should call BV Slave Process Messages regularly. Mastercommands are buffered at the serial port until BV Slave Process Messages read them. Thedevice sending Modbus master queries expects to receive a response within a specifictimeout period. You may need to adjust this timeout period on the Modbus master device ifyou do not call BV Slave Process Messages frequently enough.


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BV Slave Read 0X

Use this VI to read a 0X reference (discrete output) from the virtual controller. Referencespecifies which discrete output to read. 0X Data will contain the ON/OFF state of thediscrete output. Error will be -1 if Reference is beyond the range of the virtual controller.

BV Slave Write 0X

Use this VI to write a 0X reference (discrete output) to the virtual controller. Referencespecifies which discrete output to write. 0X Data specifies the ON/OFF state of thediscrete output. Error will be -1 if Reference is beyond the range of the virtual controller.

BV Slave Read 0Xs

Use this VI to read a series of 0X references(discrete outputs) from the virtual controller.Discrete outputs are packed eight to a byte with the Least Significant Bit containing the firstdiscrete value. Byte Position specifies the starting byte to read from the virtual controller.Number of Bytes specifies how many bytes to read. Discrete Outputs, an array of bytes,contains the data requested. Error will be -1 if Byte Position and Number of Bytesproduce a read which goes beyond the range of the virtual controller.

For example, if Byte Position is 2 and Number of Bytes is 3 the VI returns in DiscreteOutputs outputs 16 through 39.

BV Slave Write 0Xs

Use this VI to write a series of 0X references (discrete outputs) to the virtual controller.Discrete outputs are packed eight to a byte with the Least Significant Bit containing the firstdiscrete value. Byte Position specifies the starting byte to write to the virtual controller.


15

Discrete Outputs, an array of bytes, contains the data to write. Error will be -1 if BytePosition and the size of Discrete Outputs produce a write which goes beyond the rangeof the virtual controller.

For example, if Byte Position is 5 and Discrete Outputs contains 4 bytes of data the VIwrite outputs 40 through 71.

BV Slave Read 1X

Use this VI to read a 1X reference (discrete input) from the virtual controller. Referencespecifies which discrete input to read. 1X Data will contain the ON/OFF state of thediscrete input. Error will be -1 if Reference is beyond the range of the virtual controller.

BV Slave Write 1X

Use this VI to write a 1X reference (discrete input) to the virtual controller. Referencespecifies which discrete input to write. 1X Data specifies the ON/OFF state of the discreteinput. Error will be -1 if Reference is beyond the range of the virtual controller.

BV Slave Read 1Xs

Use this VI to read a series of 1X references (discrete inputs) from the virtual controller.Discrete inputs are packed eight to a byte with the Least Significant Bit containing the firstdiscrete value. Byte Position specifies the starting byte to read from the virtual controller.Number of Bytes specifies how many bytes to read. Discrete Inputs, an array of bytes,contains the data requested. Error will be -1 if Byte Position and Number of Bytesproduce a read which goes beyond the range of the virtual controller.

For example, if Byte Position is 2 and Number of Bytes is 3 the VI returns in DiscreteInputs outputs 16 through 39.


16

BV Slave Write 1Xs

Use this VI to write a series of 1X references (discrete inputs) to the virtual controller.Discrete inputs are packed eight to a byte with the Least Significant Bit containing the firstdiscrete value. Byte Position specifies the starting byte to write to the virtual controller.Discrete Inputs, an array of bytes, contains the data to write. Error will be -1 if BytePosition and the size of Discrete Inputs produce a write which goes beyond the range ofthe virtual controller.

For example, if Byte Position is 5 and Discrete Inputs contains 4 bytes of data the VIwrite inputs 40 through 71.

BV Slave Read 3X

Use this VI to read a 3X reference (input register) from the virtual controller. Referencespecifies which input register to read. 3X Data will contain the contents of the inputregister. Error will be -1 if Reference is beyond the range of the virtual controller.

BV Slave Write 3X

Use this VI to write a 3X reference (input register) to the virtual controller. Referencespecifies which input register to write. 3X Data contains the new value for the inputregister. Error will be -1 if Reference is beyond the range of the virtual controller.

BV Slave Read 3Xs

Use this VI to read a series of 3X references(input registers) from the virtual controller.Starting Reference specifies the first input register to read from the virtual controller.Number of references specifies how many input registers to read. 3X Data, an array of


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words, contains the data requested. Error will be -1 if Starting Reference and Number ofreferences produce a read which goes beyond the range of the virtual controller.

BV Slave Write 3Xs

Use this VI to write a series of 3X references (input registers) to the virtual controller.Starting Reference specifies the starting holding register to write to the virtual controller.3X Data, an array of words, contains the data to write. Error will be -1 if StartingReference and the size of 3X Data produce a write which goes beyond the range of thevirtual controller.

BV Slave Read 4X

Use this VI to read a 4X reference (holding register) from the virtual controller. Referencespecifies which holding register to read. 4X Data will contain the contents of the holdingregister. Error will be -1 if Reference is beyond the range of the virtual controller.

BV Slave Write 4X

Use this VI to write a 4X reference (holding register) to the virtual controller. Referencespecifies which holding register to write. 4X Data contains the new value for the holdingregister. Error will be -1 if Reference is beyond the range of the virtual controller.

BV Slave Read 4Xs

Use this VI to read a series of 4X references (holding registers) from the virtual controller.Starting Reference specifies the first holding register to read from the virtual controller.Number of references specifies how many holding registers to read. 4X Data, an array of


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words, contains the data requested. Error will be -1 if Starting Reference and Number ofreferences produce a read which goes beyond the range of the virtual controller.

BV Slave Write 4Xs

Use this VI to write a series of 4X references (holding registers) in the virtual controller.Starting Reference specifies the starting holding register to write to the virtual controller.4X Data, an array of words, contains the data to write. Error will be -1 if StartingReference and the size of 4X Data produce a write which goes beyond the range of thevirtual controller.


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6 CABLE PINOUTS

6.1 PC DB-25 to Modicon DB-9

5

4

3

2

1

8

7

6

RXD

TXD

CHASSIS GROUND

GDN

DSR

RTS

CTS

DTR

DCD

20

5

4

3

2

1

8

7

9

6

RX

TX

CHASSIS GROUND

DTR

SIGNAL GROUND

DSR

RTS

CTS

NO CONNECTION


5

4

3

2

1

8

7

6

RXD

TXD

CHASSIS GROUND

GDN

DSR

RTS

CTS

DTR

DCD

20

5

4

3

2

1

8

7

6

RX

TX

CHASSIS GROUND

SIGNAL GROUND

DSR

RTS

CTS

NO CONNECTION

CARRIER DETECT (ONLY ON 88

20


20

6.3 PC DB-25 to Modicon RJ45

5

4

3

2

1

8

7

6

RXD

TXD

CHASSIS GROUND

GDN

DSR

RTS

CTS

DTR

DCD

20

5

4

3

2

1

8

7

6

RX

TX

CHASSIS GROUND

SIGNAL GROUND

DSR

RTS

CTS

NO CONNECTION

CARRIER DETECT (ONLY ON 884A)

20


5

4

3

2

1

8

7

9

6

RXD

TXD

DCD

DTR

GND

DSR

RTS

CTS

RI

5

4

3

2

1

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7

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RX

TX

CHASSIS GROUND

DTR

SIGNAL GROUND

DSR

RTS

CTS

NO CONNECTION


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5

4

3

2

1

8

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9

6

RXD

TXD

DCD

DTR

GND

DSR

RTS

CTS

RI

5

4

3

2

1

8

7

6

RX

TX

CHASSIS GROUND

SIGNAL GROUND

DSR

RTS

CTS

NO CONNECTION

CARRIER DETECT (ONLY ON 884A)

20

6.6 PC DB-9 to Modicon RJ45

5

4

3

2

1

8

7

9

6

RXD

TXD

DCD

DTR

GND

DSR

RTS

CTS

RI

5

4

3

2

1

8

7

6

DSR

TXD

RXD

GND

RTS

CTS

CHASSIS GROUND

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