I'm working on a project where I need to make a network for all PCs in the site. I need about 8 Ethernet sockets in each office of the site. I found that there's already two Ethernet sockets in each office but they are connected to VoIP phones (Siemens openstage 15) .

So, I bought d-link switches (des 1008a) for each office and decided to expand the network inside each office by connecting one of the already existing sockets to the dlink switch and then connect the PCs and phones to the new switch.

The problem arose when I connected the VoIP phone to the dlink switch, it didn't boot up. I discovered that the phone is powered through Power Over Ethernet and when connected to the normal non-PoE dlink switch it doesn't work even though the main cable entering to the DLink switch is coming from a POE switch. The phone works only when connected to the cable coming from the POE switch. enter image description here

When I searched for the power specs of this specific phone model (Siemens Openstage 15) I found these specs ..

enter image description here

How can I solve this situation without expanding new cables from the main POE switch?

  • 4
    If you don't know what you are doing, please don't try changing the network or VoIP system. There may be other configuration on the network port that is connected to the VoIP phones that your new switches will provide in addition to PoE; QoS or multiple VLANs are quite common. While things may appear to work, you may have a number of issues later all resulting from the changes you are making.
    – YLearn
    Jun 14, 2014 at 21:44

5 Answers 5


A little late to the party on this one, but just came across this myself today.

Plug the VoIP phone into the PoE switch like normal. Then have the port from your VoIP phone that is labeled "PC" connect to your non-PoE switch and distribute to the rest of your PCs with the rest of the open ports from your non-PoE switch.

This may be what PsychoData is saying, but it wasn't clear to me. So kudos to you if it was :)

  • Thanks for the answer. This is exactly what I did a couple of months ago. Your effort is still appreciated.
    – Ehab
    Jun 7, 2015 at 5:35

They need to be powered either by PoE or a power adapter. PoE is going to be either a PoE switch or an inline PoE injector. The PoE injector still requires a wall outlet like the power adapter will.

  • 1
    And Power Injector can be put just besides the switch, they're not necessarily besides the phone. Be aware that you won't be able to reset your phone by cycling your switch's port though. Jun 15, 2014 at 20:35

You might could connect them as PoE Wall port -> hub -> Phone and Computer

BUT I would not guarantee that the phone will work well and this might cause intermittent connectivity issues. But it is a thought.


In place of a power over ethernet switch, you can use a device called a PoE injector. It plugs into a mains power outlet and energizes the ethernet cable like a PoE switch would. Alternatively, some phones also have the ability to use a separate power adapter. Either way, you'll need to plug something in to mains power.


I had the same problem. The answer that said to connect the main ethernet to the phone, and connect the phone "PC" port to your non-PoE switch and distribute to the rest of your PCs worked for me, thanks!


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