Moxa Technologies A51, A60 manual P e n dxi B

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A p p e n dxi B	Im p e dea Mncatc h ing a n dT erm in at ion Re si sto rs

When an electrical signal travels through two different resistance junctions in a transmission line, the mismatch will sometimes cause signal reflection. Signal reflection causes signal distortion, which in turn will contribute communication errors. The solution to this problem is to establish the same impedance at the line ends as in the line itself by terminating them with resistors.

It is normally sufficient when the value of the termination resistor equals the characteristic impedance of the transmission line. The resistors should be added near the receiving side. For example,

A50/A51

Remote site

TxDA RxDA

TxDB RxDB

RxDATxDA

RxDB TxDB

~25~

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Contents A50/A51/A60 A50/A51 A60 Copyright Notice Moxa Internet Services Table of Contents Part II A60 RS-232 Surge Protection Page Overview IntroductionIntroduction Features and SpecificationsSpecifications A50/A51 with Mounting Kit Package Check List Introduction Switch Function Description Installation ProcedureSwitch settings table of SW1 and SW2 is as follows LED IndicatorsRS-422/RS-485 Pinouts A50/A51 RJ-45 Jack Terminal Block Connector Pinouts Signals Chapter Operation Point-to-point Wire Full DuplexWire Half Duplex Multidrop SW1 DTE Simplex/Transmit, Receive A50/A51A50/A51 Self Test Operation Appendix a RS-232 Pinouts & Cable Wiring Appendix a RS-232 Pinouts and Cable Wiring Appendix a RJ-45 Connector DB-25 Female P e n dxi B Appendix B Impedance Matching and Termination Resistors Appendix C Troubleshooting Appendix C Troubleshooting Chapter Introduction Features A60 with Mounting Kit ~32~ Installation TxD indicator signal from local port RxD indicator signal from remote port ~36~ Ppendix a Appendix a ∙ RS-232 Pinouts and Cable Wiring ∙ ~40~ Ppendix B