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Linksys Lies! WAPPOE(12) isn't 802.3af !!

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Anonymous
August 21, 2005 1:07:30 AM

Archived from groups: alt.internet.wireless,comp.dcom.lans.ethernet (More info?)

I got a couple of sets of the Linksys WAPPOE12 Power-Over-Ethernet
boxes for putting WiFi APs in distant places without needing AC power
nearby, and checked very carefully to ensure that they were 802.3af
PoE, as I didn't want one of the non-compliant PoE kludges, so I could
be sure that everything was compatable, and safe to use with old and
new equipment.

OOPS! I pulled the covers off the 'injector', the piece that connects
the 48V to the spare pairs _only_ when the client device is determined
to have PoE capabilities, and found
http://compusmiths.com/WAPPoeBARsm.jpg

Not a single semiconductor (well, except the power LED), switch,
current limiter, or anything. Just slap the 48V right across the
spare pairs and hope nothing blows up. The WAPPOE injector is the
same, with the exception of a blue plastic case.

Well, I guess I know why it was so cheap. Sigh. I dunno if I even
dare try to see if the splitter will work on 802.3af switches, which
supply phantom power over the data pairs...

Grrrr.... The vendor doesn't want returns, hopefully Linksys will be
open to a refund.
Anonymous
August 21, 2005 1:07:31 AM

Archived from groups: alt.internet.wireless,comp.dcom.lans.ethernet (More info?)

On Sat, 20 Aug 2005 21:07:30 -0400, William P. N. Smith <> wrote:

>I got a couple of sets of the Linksys WAPPOE12 Power-Over-Ethernet
>boxes for putting WiFi APs in distant places without needing AC power
>nearby, and checked very carefully to ensure that they were 802.3af
>PoE, as I didn't want one of the non-compliant PoE kludges, so I could
>be sure that everything was compatable, and safe to use with old and
>new equipment.

http://www1.linksys.com/products/product.asp?grid=33&sc...

If you look at the spec sheet that's inconveniently buried in Appendix
B of the installation instructions, it claims to be IEEE 802.3,
802.3u, and 802.3af compliant.
ftp://ftp.linksys.com/pdf/WAPPOE12-UG-Rev_NC%20web.pdf
I don't think so.... Incidentally, did you notice that the new and
improved Linksys web mess no longer includes data sheets on the
product pages? I wonder what other suprises they're hiding?

Incidentally, did you read my tests of the BEFW11S4 and WRT54G routers
running off anything from about 4.0VDC to 18VDC directly?

>OOPS! I pulled the covers off the 'injector', the piece that connects
>the 48V to the spare pairs _only_ when the client device is determined
>to have PoE capabilities, and found
>http://compusmiths.com/WAPPoeBARsm.jpg
>
>Not a single semiconductor (well, except the power LED), switch,
>current limiter, or anything. Just slap the 48V right across the
>spare pairs and hope nothing blows up. The WAPPOE injector is the
>same, with the exception of a blue plastic case.

Chuckle. Notice the four resistors in the upper photograph labelled
R2, R3, R4, and R5. Could I trouble you to supply the resitor values?
These will limit the current supplied. I'm curious to calculate what
the 12V maximum load might be. There's nothing in the spec sheet and
I'm guessing that they've exceeded the DC current limit for the RJ45
connectors.

>Well, I guess I know why it was so cheap. Sigh. I dunno if I even
>dare try to see if the splitter will work on 802.3af switches, which
>supply phantom power over the data pairs...

It won't. There has to be a compatible PoE chip on the injector for
it to work.

>Grrrr.... The vendor doesn't want returns, hopefully Linksys will be
>open to a refund.

Nice work. Thanks for the clue. Post it to the Linksys support forum
on DSLReports. It might get their attention.


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
AE6KS 831-336-2558
Anonymous
August 21, 2005 3:15:05 AM

Archived from groups: alt.internet.wireless,comp.dcom.lans.ethernet (More info?)

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote:
>If you look at the spec sheet that's inconveniently buried in Appendix
>B of the installation instructions, it claims to be IEEE 802.3,
>802.3u, and 802.3af compliant.

Yeah, they lie.

>Incidentally, did you read my tests of the BEFW11S4 and WRT54G routers
>running off anything from about 4.0VDC to 18VDC directly?

Yes, I'm characterizing the WAP54G, looks like it'll do 4.20 to over
18.86V (as high as this supply will go). More news as it happens,
plus graphs and such.

>Chuckle. Notice the four resistors in the upper photograph labelled
>R2, R3, R4, and R5. Could I trouble you to supply the resitor values?

Those are 12 ohms, in series with the Ethernet input. Maybe some kind
of matching for the input? Wierd...

>These will limit the current supplied. I'm curious to calculate what
>the 12V maximum load might be. There's nothing in the spec sheet and
>I'm guessing that they've exceeded the DC current limit for the RJ45
>connectors.

On further inspection, there's a self-resetting fuse at SI1, with
"R110 4289S" marked on it. Note that they are feeding in 48V, and
using the "Power Splitter" at the other end to convert down to {12,5}V
for the device they are driving.

My programmable load is down, so I can't characterize the 12V output,
but since the WAP54G only draws about 3W (and the 802.3af PoE spec is
somewhere around 15W), I'm sure they aren't stressing anything. In
fact, at 48V, it's only drawing about 7mA (plus or minus the
inefficiency of the switching supply in the splitter).

The whole point of this exercise was to have less power (heat) at the
AP, but AFAICT the splitter dissipates more power than the AP, so I
suspect I'll go back to using a spare cable or pair to power the AP...
Anonymous
August 21, 2005 10:56:43 AM

Archived from groups: alt.internet.wireless,comp.dcom.lans.ethernet (More info?)

> OOPS! I pulled the covers off the 'injector', the piece that connects
> the 48V to the spare pairs _only_ when the client device is determined
> to have PoE capabilities, and found
> http://compusmiths.com/WAPPoeBARsm.jpg

The label says 12V?
Anonymous
August 21, 2005 10:58:44 AM

Archived from groups: alt.internet.wireless,comp.dcom.lans.ethernet (More info?)

> OOPS! I pulled the covers off the 'injector', the piece that connects
> the 48V to the spare pairs _only_ when the client device is determined

Ignore comment about 12V, brain just engaged, it's not quite 8am. :) 

David.
Anonymous
August 21, 2005 11:09:00 PM

Archived from groups: alt.internet.wireless,comp.dcom.lans.ethernet (More info?)

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote:
>William P. N. Smith <> wrote:
>>Those are 12 ohms, in series with the Ethernet input. Maybe some kind
>>of matching for the input? Wierd...

>Nope. Short circuit protection. Maximum short circuit current is:
> 48VDC / 24 ohms = 1A

Those aren't in the power supply circuit, but in the Ethernet circuit.
Since these are doing "Midspan" power injection, they are leaving the
Ethernet pairs alone and applying 48V on the 'spare' pairs.
Anonymous
August 21, 2005 11:17:58 PM

Archived from groups: alt.internet.wireless,comp.dcom.lans.ethernet (More info?)

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote:
>I used to use DC to DC inverters to run a mess of AP's on top of a
>tower. Lots of RFI from the inverters so I had to shielded power
>supplies. Then I discovered the wide range of voltages that the
>Linksys stuff will run on. I dumped the DC to DC inverter and lived
>happily ever after.

Anyone make a CAT5 splitter to allow power over the spare pairs, or am
I going to have to make my own? Linksys almost does (a couple of
their WAPPOE "power injectors" back to back), but that's kinda pricey.
8*}
Anonymous
August 22, 2005 9:04:16 PM

Archived from groups: alt.internet.wireless,comp.dcom.lans.ethernet (More info?)

William P. N. Smith <> wrote:
>The whole point of this exercise was to have less power (heat) at the
>AP, but AFAICT the splitter dissipates more power than the AP, so I
>suspect I'll go back to using a spare cable or pair to power the AP...

Not quite true, just characterised the "splitter". The power supply
is a regulated 48V supply, and the splitter draws 9.42mA DC with no
load, or about 0.45 watts.

When connected to the WAP54G V.2, which is a 3W load, the whole
assembly draws 95.0 mA, or about 4.56 watts. At this load, the
switcher in the splitter is about 66% efficient.

Still, not much point to having a power supply feeding some random
voltage to a device that'll accept something like 5-25VDC, so I'm
going back to splitting the cable between 10/100BaseT Ethernet and DC
power on the spare pairs for these particular devices.
May 19, 2011 1:16:20 PM

Maybe an adapter of some sort is in order. PanOptic Technology makes quite a few elegant solutions for providing power to both PoE and non-PoE devices over Cat-5 cabling: http://www.panoptictechnology.com/
!