Power Injector Switch

[rob998]

Hi,

 

Can I use a power injector switch to provide power to Wireless Access Points that are not PoE enabled? Something I have not tried before but would like to know before it goes ahead.

 

Thanks

[powdarrmonkey]

No. If it's not PoE enabled, how is it going to receive the power from your injector?

[wesleyw]

Beat me to it. You can't power an Access Point if it's not PoE capable.

 

Wes

[Sylv3r]

I think if you tried it your only going to damage the WAP. So I think its definitely a no - no.

[rob998]

Hi,

 

I did wonder! The problem is that my supplier failed to send me APs that supported PoE (me ordering a PoE switch at the same time didn't click in!) However when I explained they came back with this

 

Business Product

 

I have been told it works but again have never tried it. I thought the power injector switch would be just the same. Please feel free to comment

[FN-GM]

You can buy POE plug adapters, is that what you mean? We use 2 here becuase the switch ran out of ports. They work perfect.

[FN-GM]

Sorry mistake i didn't see that the WAP is not PEO i wouldn't do it in this case.

[matt40k]

Hi,

 

I did wonder! The problem is that my supplier failed to send me APs that supported PoE (me ordering a PoE switch at the same time didn't click in!) However when I explained they came back with this

 

Business Product

 

I have been told it works but again have never tried it. I thought the power injector switch would be just the same. Please feel free to comment

 

Would work,

 

The DWL-P50 Power over Ethernet adapter is a single-port splitter that provides DC power for a non-PoE-equipped device, such as a surveillance camera or a wireless access point.

 

Basically the Wifi point would get the power from the DWL-P50 which would get it from POE switch.

[rob998]

Thanks Matt,

 

The only problem I can see from the picture provided on the link i posted is the DC power socket on the splitter. Having not used one of these before I am thinking that I will have to plug in 12 plugs (as I have 12 APs) somewhere for these to work. From what you have said it sounds like I can use the PoE switch I purchased to substitute the need for the plug.

[dhicks]

it sounds like I can use the PoE switch I purchased to substitute the need for the plug.

 

I use these devices, but the other way around from you - we have PoE capable access points but no PoE switch. You only actually need the receiver end of that device listed, you don't need to use the bit that plugs in to the wall and provides power over the Ethernet cable. I don't think you can buy them separately, though. Check the connection type and voltage on your access point, the device outputs either 5v or 12v.

 

--

David Hicks

[matt40k]

@Rob998

To be honest it sounds like your Supplier messed up, from reading the stuff on the D-Link website, it sounds like you can use either 5VDC/12VDC, so you should be fine (assuming AP is D-Link, shouldn't matter tho), I assume it comes with all the bits you need.

 

Should just need to plug your switch in, plug the AP(s) into the DWL-P50(s) and the DWL-P50 into the switch and it should just work. Failing that, contact your supplier, example you've tried it, you know he's messed up, you've tried the more [expensive\harder\cr@ppy] way he's recommend, and you want POE AP.

[rob998]

Thanks guys for your help and input on this. It doesn't look like the install will be completed tomorrow.

[jam3s]

I think this is an example of what you want??

 

http://upload.wikimedia.org/wikipedia/commons/d/d8/PoE_Access_Point_v2.jpg

[sidewinder]

I think if you tried it your only going to damage the WAP. So I think its definitely a no - no.

 

Nah, you shouldnt do. Some of our network points in our office are connected to PoE ports (for testing WAPs) and we can plug various non PoE equipment into them and no problems

[jam3s]

Nah, you shouldnt do. Some of our network points in our office are connected to PoE ports and we can plug various non PoE equipment into them and no problems

 

I though POE uses the extra 4 unsed core's so it dose not effect any non POE device!

 

James

[john]

POE switches are intelligent they only push current if the device requests it as it talks about it, so if its non-POE it won't send it and thus turns the POE off on that port.

[linker3000]

I have used the D-Link PoE adaptors with IP security cameras, but have now switched to these passive power injector leads as they are cheaper, use the PSU that comes with the kit and avoid the need for the D-Link receiver to be mounted near to the item to be powered:

 

LinITX.com - Passive PoE Injector/Splitter Set

 

The only issue may be that you need to do a simple soldering job if the built-in DC plug is not the right size for the device to be powered.

 

There's some other useful stuff on the site too - for example, I carry round a tiny PS2 USB keyboard for testing and connecting to remote servers that spend most of their time without a keyboard:

 

LinITX.com - USB Tiny Thumbpad Keyboard

[matt40k]

POE switches are intelligent they only push current if the device requests it as it talks about it, so if its non-POE it won't send it and thus turns the POE off on that port.

 

The Dlink thing is POE so it will get it's power, unless it's turned off (manually).

[keithu]

Bear in mind that the POE standard specifies a DC supply of 48V. Using a passive splitter with the AP's bundled PSU will probably result in only 5V or 12V on the line. This means there will be higher current in the wire and subsequently greater resistive losses. The upshot of this is that trying to power an AP over the anything like the maximum 100m of cat5 will be hit-or-miss.

[powdarrmonkey]

I have used the D-Link PoE adaptors with IP security cameras, but have now switched to these passive power injector leads as they are cheaper, use the PSU that comes with the kit and avoid the need for the D-Link receiver to be mounted near to the item to be powered:

 

LinITX.com - Passive PoE Injector/Splitter Set

 

The details on that page are mis-representative. They are not power-over-ethernet splitters, they are just a cheap way of piggy-backing the power from your normal supply over the same cable to the access points. Do not mix and match supplies and APs with these devices, you will blow things up.

[linker3000]

The details on that page are mis-representative. They are not power-over-ethernet splitters, they are just a cheap way of piggy-backing the power from your normal supply over the same cable to the access points. Do not mix and match supplies and APs with these devices, you will blow things up.

 

To amalgamate some responses to my posting and add a bit more:

 

Agreed, thery are a cheap way of piggybacking DC over Cat 5.

 

I must go watch my kit to see whether after several months of using these devices they are about to blow up - maybe their time has come.

 

RJ jacks are typically rated at 125V AC/DC at 1.5A Max,. having grabbed some kit - I note the following:

 

IP Camera: [email protected]

Netgear AP: 7.5V@1A

 

Yes, voltage drop over a significant amount of Cat5 could be an issue, but our maximum run from cabinet to camera is around 20m and we have not had any problems.

 

I also run around 20 PoE VoIP phones on the LAN from a 3Com 4500 PoE switch and UPS and would agree that in this case there's no other sensible way to do it unless you want power bricks and mini UPSs at every desk.

 

You pays your money etc..

[matt40k]

Could you even plug such things into UPS, just thinking AC\DC issues?

[linker3000]

Could you even plug such things into UPS, just thinking AC\DC issues?

 

The whole rack is UPS protected - switches, servers, DSL kit, routers, APs etc. No problems.

[matt40k]

More thinking if you plug in, say a wireless access point, directing into a UPS, will it be ok? Not via POE switch.

[linker3000]

If you plug the mains adaptor for an Access Point into a UPS's power outlet there should be no issues with most decent kit.

 

The only caveat I'd put on that is the 5V switch mode 'wall warts' that DLink were using a 3+ years ago tended to die if the power source wasn't clean (eg: a cheap and awful UPS) - heck, they even blew sometimes if you unplugged them and plugged them back in again.