DB9 Serial Tester Recommendation(s)

Equipment, Tools & Supplies Test and Measurement
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I am new here. If this doesn’t belong in this group, please point me in the correct direction.

I am developing some PC based software code that must communicate through the USB port to a DB9 serial device via a USB to DB9 cable.

I know the serial port on the receiving device works and I know the USB port on my development PS works. What I don’t know is if my code is communicating correctly. I have tried three or four different USB-DB9 cables with no joy.

Is there a serial device that can mimic a DB9 serial device so I know that it is receiving the instructions I am sending it?

Thanks in advance!
Bill

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Hello BillR and welcome to the DigiKey TechForum.

I was able to find 2671-DB9-TERS-ND that may work for your testing.

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Nice tester, I own a very old 25 pin version and they work great fro troubleshooting TIA-232.

There’s at least a 50/50 chance the sole problem is that you need to insert a null modem between your devices to get them working.

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Edit button is missing for me today so here’s a great null modem epxlaination

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Nick,

Thanks for the link!

My question is, if there is nothing connected to the outgoing side, will it still work?

I am trying to connect to a very odd piece of equipment, and I’m not sure if it is working or not. So, I am starting with the assumption that I have to get my equipment and code working first.

Thanks!

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Paul,

Thanks. I was thinking the same thing, and tried a null modem. No joy.

This is new code and I’m not sure the USB port and/or USB to DB9 cable is working. Thus, I just want to verify I am sending and receiving to/from my computer before I try connecting to any external device. Who knows, my cables may be bad. Buying another null modem plug isn’t unrealistic.

Bill

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