[ale] Need an Ethernet cutoff relay

Alex Carver agcarver+ale at acarver.net
Mon Jul 26 14:18:24 EDT 2021


I've been searching for over a week now with no luck.

What I'm looking for is a small-ish (DIN rail mount would be ideal)
relay device that accepts a signal and will completely cut off all four
pairs of an Ethernet connection.   It should at least be shielded (so no
cheap switch boxes from Amazon adorned with Brother P-Touch labels,
those are also manual push buttons :) ).

Some of the closest I've gotten are A/B switches but they're in desktop
cases and are just too big.

Purpose:
I am going to be installing a VoIP door station to replace the doorbell
button. It's a PoE unit so I do need all the pairs. It has several
additional I/O and power ports for various uses, one of which provides a
steady 12 VDC when the unit is up. I plan to link this to a latching
relay in such a way that if the 12 VDC suddenly disappears (e.g. someone
took a baseball bat and adjusted the camera angle), it will break the
Ethernet lines to the exposed patch cable making it a dead cable which a
computer can't use.

The box itself doesn't need the latching relay, it just needs a simple
relay that is either on or off with the application of signal.  I'll
take care of the latching part separately with other external relays.

I just can't seem to find anything like this.  Just for fun I tried an
industrial PoE injector that I had handy which takes 24 VDC in but the
data lines are passed right through the unit so even with it off it
doesn't stop the drop from working as a minimum 10/100 (two pair) port.


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