B&B Electronics 232BSS4 manual Port Connections, DTE/DCE Explanation, Pin DTE, Pin DCE

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Chapter 3: PORT CONNECTIONS

Chapter 3: PORT CONNECTIONS

DTE/DCE Explanation

In order to determine the proper port connections to the 232BSS4, it is necessary to have a basic understanding of the terms DTE and DCE. RS- 232 was designed, using DB-25 connectors, for connecting a DTE (Data Terminal Equipment) device to a DCE (Data Communication Equipment) device. Each device will have inputs on pins that correspond to outputs on the same pins of the other device. For example, a DTE device will transmit data out on pin 2 (on a DB-25) and a DCE device will receive data in on pin 2 (on a DB-25). IBM PCs and serial printers are DTE devices, modems are DCE devices.

Originally the RS-232 standard specified only a 25 pin D-sub connector. Since then, the use of a 9 pin D-Sub supporting only a portion of the original RS-232 signals has been used extensively, starting with the IBM PC and migrating into other peripherals. The pinouts for this 9 pin connector have since become the EIA/TIA 574 standard. This standard specifies a DTE device that transmits on pin 3 and receives on pin 2, with the DCE having the opposite configuration.

25 Pin DTE

25 Pin DCE

9 Pin DTE

9 Pin DCE

DEVICE

LINE

LINE

DEVICE

DEVICE

LINE

LINE

DEVICE

T

2

(TD)

2

(TD)

R

T

3

(TD)

3

(TD)

R

R

3

(RD)

3

(RD)

T

R

2

(RD)

2

(RD)

T

4 (RTS)

4

(RTS)

R

7 (RTS)

7

(RTS)

T

T

R

R

5

(CTS)

5

(CTS)

T

R

8

(CTS)

8

(CTS)

T

20 (DTR)

20 (DTR)

R

4 (DTR)

4

(DTR)

T

T

R

R

6

(DSR)

6

(DSR)

T

R

6

(DSR)

6

(DSR)

T

8

(DCD)

8

(DCD)

1

(DCD)

1

(DCD)

R

T

R

T

7

(GND)

7

(GND)

5

(GND)

5

(GND)

T = RS-232 Transmitter

R = RS-232 Receiver

Figure 3.1. DTE/DCE Port Diagrams

Documentation Number 232BSS4-2907m

21

&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104 – www.bb-elec.com

B&B Electronics – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445 – www.bb-europe.com

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Contents Model 232BSS4 Buffered Smart SwitchThis product designed and manufactured in Ottawa, Illinois USA of domestic and imported parts byPage CHAPTER 4 SETUP SOFTWARE Table of ContentsAPPENDIX B CABLE CHARTS APPENDIX C BLOCK DIAGRAMDocumentation Number 232BSS4-2907m Documentation Number 232BSS4-2907m Chapter 1 - IntroductionDefault Parameters Specifications1. RS-232 Buffered Smart Switch model 232BSS4 2. Instruction Manual ChecklistThe following equipment should be in the shipping carton 3. 2 3.5 floppy disksDocumentation Number 232BSS4-2907m LED Indicators Symbols and ConventionsChapter 2 OPERATION Port Configurations Description Smart Switch Only ModeOptions Three Character Command Format Command SummaryFour Character Command Format Command ExplanationCommands Select Port A to transmit and receive - “A” VB Example Table 2.2 Send Only and Clear Buffer Control Characters Table 2.3 - Timer Values commands and the Master can initiate the next communications sequence Auto Select/Smart Switch Mode Inactivity Time Figure 2.1. Multiple Terminals to a Host Controller Using the 232BSS4 as a Buffered Splitter/CombinerFigure 2.2. Back to Back Operation Back to Back Operation mux/demuxFigure 2.3. Expanding the Number of Slave Ports Cascading Multiple SwitchesSlave Devices that Automatically Send their Data Slave Devices that Require Polling DTE/DCE Explanation Chapter 3 PORT CONNECTIONS25 Pin DTE 25 Pin DCESlave Port Connections Master Port ConnectionsIntroduction Chapter 4 SETUP SOFTWAREConnection Software Uninstall Software InstallationSelect SETTINGS, CONTROL PANEL from the Windows START menu Double Click ADD/REMOVE PROGRAMSSingle Unit Main Screen Setup Tutorial26Documentation Number 232BSS42907 Manual Back to Back Main Screen 28Documentation Number 232BSS42907 Manual Default Parameters Copying Parameters Between SwitchesDocumentation Number 232BSS42907 Manual DECIMAL to HEX to ASCII CONVERSION TABLE Appendix A ASCII Character CodesASCII Appendix A Pins 6, 8, & 20 looped back internally on the 232BSS4 Appendix B Cable ChartsChart B.1. DTE PC DB25 Connector to Master Port Chart B.2. DTE PC DB9 Connector to Master PortAppendix B Cable Charts Chart B.3. DCE Modem DB25 Connector to Master Port Pins 6, 8, & 20 looped back internally on the 232BSS4Chart B.4. DCE Modem DB9 Connector to Master Port Chart B.5. Ports A - D DTE to DTE PC DB25 Connector Pins 1, 4, & 6 looped back internally on the 232BSS4Chart B.6. Ports A - D DTE to DTE PC DB9 Connector Chart B.7. Ports A - D DTE to DCE Modem DB25 ConnectorChart B.8. Ports A - D DTE to DCE Modem DB9 Connector Pins 1, 4, & 6 looped back internally on the 232BSS4Documentation Number 232BSS42907 Manual MASTER Appendix C Block DiagramUART UART UARTDocumentation Number 232BSS42907 Manual DECLARATION OF CONFORMITY Appendix D Declaration of Conformity