How to perform a loopback test on a RS232 system
Potential Symptoms
- How do you determine which pins to jumper on DB9 or DE9 male connection serial port on a computer/desktop/laptop when performing a loopback test?
- How to do I perform a loopback test on a USB to RS232 serial adapter?
Environment
- Product Family: Message Displays
- Product: Galaxy
- Component: Serial Communication, USB to Serial adapter (e.g. Prolific, Moxa), Computer with 9 pin male serial/COM port
- Control System:
Resolution
- Use a paper clip (or other conductor) to perform loopback and jumper pins 2 & 3 together
- When looking at the serial DE-9/DB9 male connection, go to the column/row that has 5 pins.
- With a USB to serial adapter, orient the adapter so that the 5 pins are on the top (more pins across the top then the bottom)
Vertical Orientation DE9/DB9
- If the column of 5 pins is to the right of 4-pin column, then pins 2&3 will located near top of the 5-pin column (i.e. pins numbered 1-5 top-down)
- If the column of 5 pins is to the left of the 4-pin column, then pins 2&3 will be located closest to the bottom of the 5-pin column (i.e. pins numbered 1-5 starting at bottom)
Horizontal Orientation of DE9/DB9
- If the 5-pin row is located on top of 4 pin row, pins 2&3 will be located closest to the left on the 5-pin row (pins numbered 1-5 from left to right)
- If the 5-pin row is located under the 4-pin row, pins 2&3 will be located closest to the right on the 5-pin row (pins numbered 1-5 from right to left)
- To view a video on performing loopback testing on: Performing an RS232 Loopback Test.
KB ID: DD2127080
DISCLAIMER: Use of this content may void the equipment warranty, please read the disclaimer prior to performing any service of the equipment.
DAKTRONICS DOES NOT PROMISE THAT THE CONTENT PROVIDED HEREIN IS ERROR-FREE OR THAT ANY DEFECTS WILL BE CORRECTED, OR THAT YOUR USE OF THE CONTENT WILL PROVIDE SPECIFIC RESULTS. THE CONTENT IS DELIVERED ON AN "AS-IS" AND "AS-AVAILABLE" BASIS. ALL INFORMATION PROVIDED IN THIS ARTICLE IS SUBJECT TO CHANGE WITHOUT NOTICE. DAKTRONICS DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING ANY WARRANTIES OF ACCURACY, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. DAKTRONICS DISCLAIMS ANY AND ALL LIABILITY FOR THE ACTS, OMISSIONS AND CONDUCT OF YOU OR ANY THIRD PARTIES IN CONNECTION WITH OR RELATED TO YOUR USE OF THE CONTENT. ADJUSTMENT, REPAIR, OR SERVICE OF THE EQUIPMENT BY ANYONE OTHER THAN DAKTRONICS OR ITS AUTHORIZED REPAIR AGENTS MAY VOID THE EQUIPMENT WARRANTY. YOU ASSUME TOTAL RESPONSIBILITY FOR YOUR USE OF THE CONTENT AND ANY LINKED CONTENT. YOUR SOLE REMEDY AGAINST DAKTRONICS FOR DISSATISFACTION WITH THE CONTENT IS TO STOP USING THE CONTENT. THIS LIMITATION OF RELIEF IS A PART OF THE BARGAIN BETWEEN THE PARTIES.
The above disclaimer applies to any property damage, equipment failure, liability, infringement, or personal injury claim arising out of or in any way related to your use or application of the content, whether such claim is for breach of contract, tort, negligence or any other cause of action.