Pinout For Serial Ports and Loopback Test

Publish Date: Feb 09, 2018 | 2 Ratings | 3.00 out of 5 | Print


This article provides pinout information for serial ports. It will also tell you which pins to connect for a loop back test.

1. Introduction

RS-232 is the single ended serial protocol and RS-485 and RS-422 are differential serial protocol. The pinout for RS-232, RS-422 and RS-485 is shown below figure.



A loopback test is a test in which a signal in sent from a communications device and returned (looped back) to it as a way to determine whether the device is working right. The figures below will show you what pins you need to connect to perform loopback test on RS-232 and RS-422/RS-485 respectively.



RS-422 and RS-485


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2. Additional Resources

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