# Opennmc

OpenNMC is an open-source UPS network-management platform combining Buildroot Linux, Network UPS Tools, and a web application, with extensible software and hardware interfaces.

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## OpenNMC is an open replacement for expensive APC management cards

DevFeed: [OpenNMC is an open replacement for expensive APC management cards](<https://devfeed.tech/articles/opennmc-is-an-open-replacement-for-expensive-apc-management-cards-10474.md>)

Original publisher: [Read original article](<https://www.jeffgeerling.com/blog/2026/opennmc-apc-ups-replacement-card/>)

Author: jeff@jeffgeerling.com (Jeff Geerling)

Published: 2026-09-08T16:00:00Z

Content type: article

Language: en

Sources: [Jeff Geerling](<https://devfeed.tech/sources/jeff-geerling.md>)

Topics: [Opennmc](<https://devfeed.tech/topics/opennmc.md>), [Homelab](<https://devfeed.tech/topics/homelab.md>), [Hardware](<https://devfeed.tech/topics/hardware.md>), [Open Source](<https://devfeed.tech/topics/open-source.md>), [GitLab](<https://devfeed.tech/topics/gitlab.md>), [Ethernet](<https://devfeed.tech/topics/ethernet.md>), [USB](<https://devfeed.tech/topics/usb.md>), [Crowd Supply](<https://devfeed.tech/topics/crowd-supply.md>), [Reddit](<https://devfeed.tech/topics/reddit.md>)

Tags: [apc](<https://devfeed.tech/tags/apc.md>), [ethernet](<https://devfeed.tech/tags/ethernet.md>), [firmware](<https://devfeed.tech/tags/firmware.md>), [gitlab](<https://devfeed.tech/tags/gitlab.md>), [hardware](<https://devfeed.tech/tags/hardware.md>), [homelab](<https://devfeed.tech/tags/homelab.md>), [open-source](<https://devfeed.tech/tags/open-source.md>), [opennmc](<https://devfeed.tech/tags/opennmc.md>), [sponsored](<https://devfeed.tech/tags/sponsored.md>), [ups](<https://devfeed.tech/tags/ups.md>), [usb](<https://devfeed.tech/tags/usb.md>)

### AI overview

The article tests OpenNMC, an open-source replacement for proprietary APC UPS management cards. It describes hot-pluggable installation, built-in NUT server support, Ethernet and wireless connectivity, and an initial USB-C serial setup.

### Source excerpt

UPSes are typically the most boring part of your homelab, but they're important. One of their main jobs is to give servers time to shut down safely if the power goes out. Another job is to condition your power so your servers can run smoothly. To do both of those things well, you need a smart interface. And at least with APC, there are tons of older UPSes that use Network Management Cards. The one pictured below is the NMC 2, and I pulled out of my old APC Smart-UPS 2200 XL (pictured above).