I want to make an ethernet kill switch. I plan on taking 2 keystone jacks and wiring them to each other. Then putting a rocker switch between the orange wire to kill internet. How ever I have a rocker switch with an LED that I would love to have lit when internet is on. It has 3 prongs: POWER | ACC | GROUND. I know how I would wire this if I was using it for something that how power going to it, but what I would love to do is use it for this internet kill switch and then hook up 2 AAA batteries to it as well. So I am wondering if there should be an concern for the computer or ethernet switch from the 2 AAA batteries. I plan to run the ORANGE wire to the ACC and GROUND prongs. Then I would also have to hook up the 2 AAA batteries to the POWER and GROUND prongs. Does that sound correct and safe for the hardware?

I am a complete noob when it comes to electrical so any help is much appreciated!


closed as unclear what you're asking by Chris Stratton, PeterJ, Daniel Grillo, Dmitry Grigoryev, Dave Tweed Aug 29 '16 at 12:02

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  • \$\begingroup\$ No. An Ethernet signal would not appreciate a 3V DC power connection on either side of one of the wires. \$\endgroup\$ – Passerby Aug 27 '16 at 4:32
  • \$\begingroup\$ @Passerby The 3V circuit would only be connected at one point to the Ethernet circuit, so it shouldn't affect it. \$\endgroup\$ – immibis Aug 27 '16 at 4:54
  • \$\begingroup\$ However, note that high-speed data signals tend to be quite sensitive to things like geometry - it's possible that just putting the rocker switch in the data line will break it (or slow it down). \$\endgroup\$ – immibis Aug 27 '16 at 4:54
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    \$\begingroup\$ Yes, the Impedance of the differential pair is important. At minimum a dpst for both wires of a pair is needed to minimize any interference. But a physical switch is not to spec. \$\endgroup\$ – Passerby Aug 27 '16 at 5:04
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    \$\begingroup\$ A so-called 'managed switch' is a common Ethernet component that can disconnect a network connection and reconnect it reliably. Mechanical switching is noncompliant with 1000baseT and other wiring standards. \$\endgroup\$ – Whit3rd Aug 27 '16 at 5:50

Don't interfere with the signal wiring. You might get it to work or it may cause intermittent problems.

Instead use the switch to cut power to a hub or router. This has the advantage that you can use the hub power supply to light the LED and then be battery free.

If the indicator is a plain LED then you need to add a current limiting resistor.


simulate this circuit – Schematic created using CircuitLab

Figure 1. How to wire up for a 12 V supply.

There may already be a resistor in the switch but you have not supplied a part number or link to a datasheet so we can't check.


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