Network card with relay in case of power failure

Warren Kumari warren at
Thu Jun 18 16:01:49 UTC 2020

On Wed, Jun 17, 2020 at 4:15 PM Dovid Bender <dovid at> wrote:
> Hi,
> I am sorry if this is off topic.I was once demoed a network device that had two interfaces. The traffic would go through the device. If there was a power cut or some other malfunction there would be a relay that would physically bridge the two network interfaces so the traffic would flow as if it was just a network cable. Is anyone aware of such a network card or device?

Yup -- the Peribit devices used to do this - one of them died, so I
decided to repurpose it into a webserver.
Their implementation seemed to just be a PCI card and some relays -
Ethernet went into RJ-45 jacks on the relay card, and PCI voltage held
the relays "on", routing the Ethernet to an internal NIC. When the
device lost power the relays would close, and bypass the device. The
PCI card also had some chips on it, but I never bothered trying to
figure out if they were for heartbeat, or just power conditioning,

(I was going to reply to this thread yesterday and include photos, but
I think I've thrown the cards out... )

> TIA.

I don't think the execution is relevant when it was obviously a bad
idea in the first place.
This is like putting rabid weasels in your pants, and later expressing
regret at having chosen those particular rabid weasels and that pair
of pants.

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