Reply
New Member
TravisA
Posts: 23
Registered: ‎01-10-2010
Posts: 23
Kudos: 1
Registered: 01-10-2010

Dead Laptop Ethernet (PoE Fed)

As I sit and look at my laptop with a fried LAN port I ask myself why isn't ubiquiti using IEEE 802.3af ?? I knew full well what would happen if the ports were reversed and PoE was fed into the laptop yet that didn't stop someone else from making the mistake. We were working on the equipment on site today and I had my laptop plugged into an ethernet cord. My buddy grabbed the ethernet cord and plugged it into the PoE side of the injector. In an instant smoke was pouring out of the laptop.

So far we are down 1 switch port and 1 laptop LAN to PoE. How many more ethernet interfaces need to be wiped out?

I love the equipment however this just SUCKS!!!

A warning to all.. KEEP EVERYONE AWAY WHEN WORKING ON THIS EQUIPMENT!!!

I would be more than willing to wait another moment for the power negotiation. Please add some protection to this wonderful long distance equipment.
Regular Member
InoX
Posts: 583
Registered: ‎09-18-2008
Posts: 583
Kudos: 22
Registered: 09-18-2008

Re: Dead Laptop Ethernet (PoE Fed)

this just SUCKS!!!

Did you ever think that maybe you/others suck?
Never happeed to me. In fact it happened once, not with UBNT, but the lan part of the laptop is still working very good. Intel gigabit inside.
Established Member
Idea
Posts: 1,072
Registered: ‎10-28-2010
Posts: 1072
Kudos: 295
Solutions: 6
Registered: 10-28-2010

Re: Dead Laptop Ethernet (PoE Fed)

I think the reason is purely cost. It's about as silly as using 1/4inch phono plugs for both line level and post-amplified speaker signals. That being said, I've never messed either of the up.
Still it's a problem that deserve some thought, if only for CPE's with reckless/clueless owners.
Established Member
Ron
Posts: 933
Registered: ‎02-23-2008
Posts: 933
Kudos: 22
Registered: 02-23-2008

Re: Dead Laptop Ethernet (PoE Fed)

Since the first installation we did, we have explained to the customer to NEVER connect the POE side of the POE injector to ANYTHING except the antenna. We make sure to repeat it 2 or 3 times and tell them clearly that if they make this mistake, their equipment WILL go up in smoke.

So far, less than 1% of our customers, as far as we know, have damaged their equipment.

Pay attention while working and everything will be OK.
Veteran Member
mhoppes
Posts: 12,602
Registered: ‎06-23-2010
Posts: 12602
Kudos: 3455
Solutions: 49
Registered: 06-23-2010

Re: Dead Laptop Ethernet (PoE Fed)

Did you ever think that maybe you/others suck?
Never happeed to me. In fact it happened once, not with UBNT, but the lan part of the laptop is still working very good. Intel gigabit inside.


Let's keep this professional. With that said... Aren't the laptop jacks suppose to avoid pulling power off the POE if they detect it? What's to keep someone from plugging a laptop into a POE enabled switch port? You don't have workstations blowing up all over the place.
Sent via alt.hardware.wireless.ubnt reflector

On-Location airMax Training for Groups of 4 or more.
Send PM for more information.
Regular Member
mhohman
Posts: 327
Registered: ‎11-15-2008
Posts: 327
Kudos: 80
Solutions: 4
Registered: 11-15-2008

Re: Dead Laptop Ethernet (PoE Fed)

We secure a ziptie between the rj45 connector and the tab. Makes it very difficult to disconnect with out a pair of cutters.
Senior Member
rockhead
Posts: 3,190
Registered: ‎05-02-2008
Posts: 3190
Kudos: 2146
Solutions: 16
Registered: 05-02-2008

Re: Dead Laptop Ethernet (PoE Fed)

I have occasionaly been working too fast and sloppy and plugged a POE where it didn't belong. It has not cost me anything but a moment of alarm thus far, and I get more careful over time as I know this luck will not always hold. I certainly wouldn't blame anything but my own sloppiness if the "smoke" was released from a chip due to this.
I have seen a few ethernet ports fail after massive static discharges but that's a different thing altogether.
Gnawing at the ankles of the telecom giants since 2008.
Established Member
Bbobb
Posts: 2,153
Registered: ‎01-13-2010
Posts: 2153
Kudos: 72
Registered: 01-13-2010

Re: Dead Laptop Ethernet (PoE Fed)

I am really intriged by this and would be very interested in knowing what Laptop was involved.... For this to be an issue one has to presume that the 4,5/7,8 pins were connected to something and I can't imagine why they would do that.

I know some guys are really anal about connecting unused inputs on ICs to something to avoid noise or indeterminate states but this is a connector. It you connected them all to ground that weould have shorted the POE and they seem to survive that so that leaves connecting them to the positive rail which would have internal power on the connector or connected anywhere else which has to be just plain off the map.

I was concerned about this when I first used POE devices and went around for some time with an Ethernet plug and meter and never encountered anything that appeared to have those pins connected that wasn't POE powered or POE power supply

We don't even think about it as a result but if his experience was on anything that exists to any extent out here in the wild I would like to know WTF it is!

Bob
Established Member
Idea
Posts: 1,072
Registered: ‎10-28-2010
Posts: 1072
Kudos: 295
Solutions: 6
Registered: 10-28-2010

Re: Dead Laptop Ethernet (PoE Fed)

1000Base-T uses all 4 pairs.
PoE is still possible but I believe it runs on data lines as phantom power, when the gear supports it.
Member
ktc
Posts: 131
Registered: ‎11-07-2010
Posts: 131
Kudos: 6
Registered: 11-07-2010

Re: Dead Laptop Ethernet (PoE Fed)

I've had two laptops with gigabit Ethernet and i'm sure Ive plugged in poe to the old one, and i think my new one with intel gig.

Linksys devices seem to just smell bad after you do it, not sure how long you wait for smoke.
Established Member
Ron
Posts: 933
Registered: ‎02-23-2008
Posts: 933
Kudos: 22
Registered: 02-23-2008

Re: Dead Laptop Ethernet (PoE Fed)

For this to be an issue one has to presume that the 4,5/7,8 pins were connected to something and I can't imagine why they would do that.


gigabit ethernet
Established Member
Ron
Posts: 933
Registered: ‎02-23-2008
Posts: 933
Kudos: 22
Registered: 02-23-2008

Re: Dead Laptop Ethernet (PoE Fed)

What's to keep someone from plugging a laptop into a POE enabled switch port? You don't have workstations blowing up all over the place.


PoE switches use a different POE techology as compared to the passive PoE used by UBNT. The UBNT PoE injectors do not do any type of detection, which reduces cost and complexity.
New Member
Treetop
Posts: 17
Registered: ‎01-15-2011
Posts: 17
Registered: 01-15-2011

Ubiquiti - please add POE warning

PoE switches use a different POE techology as compared to the passive PoE used by UBNT. The UBNT PoE injectors do not do any type of detection, which reduces cost and complexity.


Ubiquiti:
Please consider adding a warning on the POE adapters.
Thanks,
Al
Ancient Member
WHT
Posts: 29,005
Registered: ‎03-17-2008
Posts: 29005
Kudos: 5165
Solutions: 95
Registered: 03-17-2008

Re: Dead Laptop Ethernet (PoE Fed)

As I sit and look at my laptop with a fried LAN port I ask myself why isn't ubiquiti using IEEE 802.3af ??
For the same reason that For the same reason that 99% of the other wireless product manufactures don't.

I have occasionaly been working too fast and sloppy and plugged a POE where it didn't belong.
I must have inadvertently plugged a PoE cable into a cheap assed no-name generic $9 switch and smelled a fried resistor. I immediately guessed what I did and hit the power strip switch. I was pretty flustered and unplugged EVERYTHING instead of tracing back what I did wrong.
WHT = Short Form Acronym for "You couldn't handle me even if I came with instructions!"
Well engineered projects are indistinguishable from crazy ideas.

Speed, distance, reliability, cost...Pick three.
...World's First Ubiquiti AirMax WISP....
Senior Member
rockhead
Posts: 3,190
Registered: ‎05-02-2008
Posts: 3190
Kudos: 2146
Solutions: 16
Registered: 05-02-2008

Re: Dead Laptop Ethernet (PoE Fed)

Ubiquiti:
Please consider adding a warning on the POE adapters.
Thanks, Al


I thought I smelled BBQ, what did you cook ?
Gnawing at the ankles of the telecom giants since 2008.
Established Member
MaximumISP
Posts: 1,630
Registered: ‎01-11-2008
Posts: 1630
Kudos: 212
Registered: 01-11-2008

Re: Dead Laptop Ethernet (PoE Fed)

Gotta say I/we have made this mistake a few times in haste
so far it hasnt cooked anything the poster should be able
to get a pmcia ethernet card for the laptop not as nce as onboard
but at least it will be usable

Regular Member
davey
Posts: 363
Registered: ‎04-23-2008
Posts: 363
Kudos: 34
Registered: 04-23-2008

Re: Dead Laptop Ethernet (PoE Fed)

Yes in haste I have done it too, even to customer equipment once but got away with it. Probably 100M ports.
Established Member
sakita
Posts: 1,173
Registered: ‎10-20-2009
Posts: 1173
Kudos: 161
Registered: 10-20-2009

Re: Dead Laptop Ethernet (PoE Fed)

I *really* wish someone would sell magic smoke in a dispenser that allowed it to be pushed back into devices...

Didn't it happen that somewhere back in time somebody realized that there were 'extra' pairs of wire available in the standard Ethernet port and then utilized them... in fact several somebodies did that each in their own incompatible manner.

Since then great effort was put into standardizing power injection... of course making it more complicated and expensive at the same time.

Meanwhile the original use for those 'extra' wires came into play (gigabit) and now all of the wires are used.


...this is the essense of value engineering. There is a tradeoff and that tradeoff is saving a few bucks and potentially frying gear.

Question, aren't there slightly more expensive POE injectors (not 802.3AF) that will work with Ubiquiti that do have current sensing? This means a choice - do I want to take the risk or pay a few extra bucks.
Today is an average day: Worse than yesterday, but better than tomorrow.
Reply