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APC UPS Data Center & Enterprise Solutions Forum
Schneider, APC support forum to share knowledge about installation and configuration for Data Center and Business Power UPSs, Accessories, Software, Services.
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Posted: ‎2025-05-20 01:19 AM
Hi
I have an APC SMT750RMI2U UPS that is working fine, until I connect it to the network with a CAT5 cable.
As soon as I do this, about 5 seconds later it shuts down with a message "Output off by Software"
I had a look in Powerchute (connected it with a USB cable) and can't see any relevant settings or anything on the logs.
I tried disconnecting and reconnecting the battery but it didn't solve the issue.
Any help much appreciated
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Posted: ‎2025-05-20 05:37 AM
Show me a photo of the rear of the system and where you connected the CAT5 RJ45 Ethernet cable.
If you connected your CAT5 Ethernet cable to RJ50 Serial Ethernet port on the rear of the UPS frame .
That’s why it shut down because that specific port uses a proprietary (internally wired) serial cable.
If you connected your CAT5 Ethernet cable to a NMC. Show me all the output power settings.
Questions Ask . . . 👍
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Posted: ‎2025-05-20 05:37 AM
Show me a photo of the rear of the system and where you connected the CAT5 RJ45 Ethernet cable.
If you connected your CAT5 Ethernet cable to RJ50 Serial Ethernet port on the rear of the UPS frame .
That’s why it shut down because that specific port uses a proprietary (internally wired) serial cable.
If you connected your CAT5 Ethernet cable to a NMC. Show me all the output power settings.
Questions Ask . . . 👍
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Posted: ‎2025-05-21 12:58 AM
Hi there
Thank you! I think you solved it
I was connecting the network cable to the "serial" RJ45 port.
We have some UPSs that don't have a Network port so I got confused.
Solved!
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Posted: ‎2025-05-21 06:06 AM
Appreciate you confirming the root cause so please do mark my previous reply as a solution.
So it may help the next person asking the same.
Rock On . . . 👍
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