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I was wondering if leaving an active Ethernet port with no plug in it was safe . We have one in our kitchen right next to our face level and I was wondering if leaving it unplugged in the open was safe like does any radiation or infrared laser/light come out of it. Might sound very paranoid but I'm curious.
John doe
Posted 2018-03-19T23:36:06.757
Reputation: 357
129
First: you are safe.
I'm assuming you have the standard plug that looks like this:
but if it is a wire that plugs into a laptop or desktop computer, the chances are good that it is a standard RJ45 outlet.
In that case, while the device on the other end could supply power to the port,
If you are using fibre, you are still safe. A fibre port does output laser light (see here), but it is a "Class 1" laser (see here), so you'll have to try kind of hard to get hurt by it. Plus, if it is fibre, there is absolutely no electrical hazard (fibre doesn't conduct electricity)
It is always reasonable to be interested in safety, and to seek out information to ensure your safety. Keep up the good work.
Slartibartfast
Posted 2018-03-19T23:36:06.757
Reputation: 6 899
24As long as we're being cautious, technically everything emits radiation of some form. – Dean MacGregor – 2018-03-20T05:13:42.810
96Including the requester. And bananas. Probably more from bananas. – Slartibartfast – 2018-03-20T05:22:42.823
42Bananas - both a unit of scale and radioactivity... – Journeyman Geek – 2018-03-20T07:32:26.700
44
One might ask if @Slartibartfast is serious. He is. https://en.wikipedia.org/wiki/Banana_equivalent_dose
– Christian – 2018-03-20T10:18:25.9276@JourneymanGeek Don't mix up radiation and radioactivity... – Radovan Garabík – 2018-03-20T11:44:51.887
35
The only correct radiation chart is the XKCD radiation chart. https://xkcd.com/radiation/
– djsmiley2k TMW – 2018-03-20T13:15:55.9772
This XKCD radiation chart is more relevant to the question: https://imgs.xkcd.com/comics/electromagnetic_spectrum.png
– Harry Tsai – 2018-03-20T17:59:39.80010I guess the easiest way to get hurt by a class 1 fiber cable is to use it as a whip? – John Dvorak – 2018-03-20T18:04:45.630
Could you please change the externally hosted image to one that is hosted by Stack Exchange, or better yet make it inline? That way if Lowes changes their website and gets rid of the picture, the answer still works. – Thunderforge – 2018-03-20T21:44:22.210
1"it is a standard RJ45 outlet" Network cables really do not use RJ45, which is a keyed connector, specifically for voice. Data cables use 8P8C connectors, commonly, and incorrectly, called RJ45. – Ron Maupin – 2018-03-21T05:17:25.800
3@DeanMacGregor Generally, people are asking whether a thing emits ionizing radiation rather than just general radiation when they're talking about radiation. Whether they're aware of types of radiation is somewhat irrelevant to the question being asked though. – John Hamilton – 2018-03-21T08:03:45.450
@djsmiley2k last line in that chart disproves your statement :) still cool chart – Snow – 2018-03-22T19:08:39.940
1A ringing POTS line has enough voltage to cause an unpleasant shock, but I don't know if sticking your finger in an RJ11 jack, such as the one in your picture, can deliver that shock. My main phone is wall-mounted with the wire blocked by a cabinet so that the cat can't chew on it. – Mark Plotnick – 2018-03-23T11:01:43.727
54
The question I'd be asking is whether your ethernet is safe from your kitchen? You wouldn't want to splash liquid into the port and cause corrosion of the socket, as then devices plugged in there in the future might not work. To protect the socket, search for a cheap RJ45 Dust Cover on Amazon/Ebay/your local computer store.
Another 'fix' is to take a old ethernet cable with a RJ45 plug on it, and cut it off leaving a inch or so of cable. Plug this into the port to keep dirt/dust out.
Sir Adelaide
Posted 2018-03-19T23:36:06.757
Reputation: 4 758
1Every time I have an Ethernet cable fail, I cut off the ends like this and keep them. One reason I like to have some around is to fold a piece of duct tape in half over the cable and write "BAD" on both sides with a permanent marker, to tag jacks and switch ports suspected/known to be bad, so that no one will try to use them. This is another good use for what would otherwise be thrown away. – Monty Harder – 2018-03-23T21:22:41.403
Not jus tthe kitchen - any kind of port that is in reach of smaller children could end up with food wedged in it. Having worked in a high school, I've seen cretins jam metallic foil inside them too. – Criggie – 2018-03-24T21:30:51.440
10
Completely safe. You can even touch the contacts. Also, even if there is a PoE (Power over Ethernet) injector or supply on the other end, I believe that power is not sent over the wire unless a compatible receiving device is connected at the other end.
Rich M
Posted 2018-03-19T23:36:06.757
Reputation: 356
2Isn't PoE low voltage & low current DC anyway, so shouldn't be any more harmful that touching both ends of a AA or D or 9V battery. I wouldn't recommend putting your tongue in there, but should still be a lot safer than the power outlets. – Xen2050 – 2018-03-21T03:03:37.933
The various PoE standards all use in the region of 48 V and at least 350 mA, that's a pretty good jolt (and enough to be dangerous if applied across the heart). But you're correct, PoE isn't supposed to apply power until negotiations have been made. – Hobbes – 2018-03-21T19:51:33.943
What if you lick it? – coinbird – 2018-03-23T15:36:45.873
@Hobbes Unless you stab yourself with a fork and then use that fork (still in the wound) to short the socket, said jolt is never going to reach your heart. – Christian – 2018-03-23T16:11:11.013
1Stick a finger on your left hand in the socket, and your right hand on a nearby grounded object (maybe the kitchen sink). Voila, current path across the heart. – Hobbes – 2018-03-23T16:33:46.710
7
If it's old enough ethernet - 10BASE5 - then it does need a terminator to stop the waves reflecting at the end and radiating a tiny amount of energy.
The terminators will look like this, from https://en.wikipedia.org/wiki/Electrical_termination
If it's a more modern ethernet, then you don't need to terminate. The termination only matters in that it degrades the signal, there is little radiation and nothing that would affect safety - mostly it's there to stop the energy bouncing back into the wire and confusing the electronics.
Pete Kirkham
Posted 2018-03-19T23:36:06.757
Reputation: 230
5Worth noting that an unterminated 10BASE5 cable is basically a low-powered radio transmitter. – Mark – 2018-03-20T23:53:01.827
@Mark from which we should all protect ourselves because of that ever-present danger electromagnetic hypersensitivity... – RonJohn – 2018-03-21T00:41:23.310
4Huh, from memory, a COAX network (like pictured) doesn't actually work without a terminator, right? Doesn't the terminator connect the inside wire to the outside? Could be misremembering. – Steve Bennett – 2018-03-22T05:35:27.420
1@SteveBennett it connects it with a resistor to prevent the signal reflecting back into the cable. Whether the network still works depends on how long the cable is (which determines whether the reflection of the signal off the end constructively or destructively interferes, or just combines bits in the packet with ones that were sent a few moments ago), and IIRC to some extent the quality of the network card; the network when I was at university would get slow with lots of packet losses and someone from tech support would come round and check all the terminators. – Pete Kirkham – 2018-03-22T09:33:40.023
2Sorry, @PeteKirkham, but that is incorrect. The terminators are required regardless of the cable length. Without them the cable will not present the correct impedance to the transceivers, so the transceivers will sense "collision" at all times. Even using 75 ohm instead of the standard 50 ohm terminators should cause this problem, though many manufacturers fudged the spec a little so they'd work anyway, as it was a common mistake to use RG59 (75 ohm) instead of RG58 (50 ohm). – Jamie Hanrahan – 2018-03-23T01:22:07.823
Funny thing, though: with a cable short enough that you wouldn't have to worry about signal reflections, you could get away with just one 25 ohm terminator, anywhere on the cable, instead of a 50 ohm at each end! Because to DC they'll act the same. – Jamie Hanrahan – 2018-03-23T01:22:47.940
@JamieHanrahan I may have misremembered about why the network at the university lost packets - it was about 25 years ago. I was thinking of long cables, not short ones, but doing the math for 10Base5 says a cable long enough that a packet can be received before the reflection has time to interfere with it would make the cable unfeasibly long - at 10Mb/s a packet is tens of miles long; I must have been thinking about faster systems. – Pete Kirkham – 2018-03-23T09:28:50.413
@PeteKirkham: It's a shared medium, so https://en.wikipedia.org/wiki/Carrier-sense_multiple_access_with_collision_detection between hosts is harder if they're farther apart (in cable length). Or maybe if the reflection has to be far enough away for it to look like another host starting to transmit, instead of still this host's own signal? Also, the signal to noise ratio is probably worse on big installations, between distant hosts and with many other hosts acting as a load. And finally, T junctions probably make everything worse.
– Peter Cordes – 2018-03-25T14:15:28.850I don't think I ever had a small 10base2 setup, though. Probably the biggest issue with a large setup that runs to everyone's office is that it makes it easy for someone to accidentally dislodge a terminator, and harder to inspect, and one person's problem affects everyone. So yeah, worse downsides from the same physics / electronics problem whether or not our guesses that small installations might be more resilient to bad termination. – Peter Cordes – 2018-03-25T14:16:57.807
38Just to add folks - while there's flaws in the premise of the question, snarky misleading comments are not cool. – Journeyman Geek – 2018-03-20T10:39:38.597
13The stack exists to build a knowledge base. There should be questions from beginner to extra-advanced expert level. So long the requirements of the help center are met, the level of expertise of the poster is not an issue. – Mindwin – 2018-03-20T12:43:57.460
3What kind of Ethernet port? Is it an RJ45 socket (aka 8P8C, for twisted-pair), or is it a BNC socket (for coaxial cable)? (Not that it makes a difference - it's low-voltage, and RJ45 sockets are usually shuttered, too). – Toby Speight – 2018-03-20T13:02:44.993
5There'd actually fibre optic wall sockets too, but its unlikely to be found in a kitchen. If there's protective covers, leaving them on is a good idea to protect the connectors not the people ;p – Journeyman Geek – 2018-03-20T13:43:24.957
1It would be a good idea to update the question with the type of ethernet port, because if it does happen to be a coax port (not likely in 2018) the answer would be different – Thomas Carlisle – 2018-03-20T18:39:00.857
1Why would there be an Ethernet port in the kitchen, are you sure it's not the phone outlet? – n0rd – 2018-03-20T21:33:24.903
@n0rd in the time when 802.11a ruled the airwaves, and WAP "protected" us all, putting an Ethernet drop in the kitchen was quite reasonable. – RonJohn – 2018-03-21T00:43:53.377