Hi guys...
I know this is a very dumb question but can I connect a POE switch to a non POE switch?

My building has 3 floors and I have a few POE devices in each floor. So, I plan to put a POE switch in each floor, that means I have 3 POE switch. All the devices will have to connect to my main server so I need another main switch which a cable from each of the POE switch will connect to. My question is, do I use a POE switch for the main switch or I can use a non POE switch?

 

You can use a non-POE switch for the main switch. Personally, I would disable POE on the ports used for the uplink to the main, non-POE switch.

 

The 802.3af standard will not apply power to a non-PoE device.
Also, many PoE switches have dedicated non-PoE uplink/trunk ports you may use.

 

Yes generally with POE it doesn't matter. As said there are negotiations, etc for POE. I have seen POE switch in enterprise network running to PCs, phones, APs, etc. due to design it doesn't matter much. Not sure you have ever looked at a motherboard, or even most NIC cards. There is a small box on them (newer ones changed this somehow, but is still there somewhere most likely.) This box is called a lan isolation transformer. what i understand it to do is sort of an isolation device. Lan traffic is made of bits on/off, etc that drives this transformer to either create signals on the line or read them off the line. I think also how you can have all 4 pair used in a cable yet still have POE.

I think the powered lines are made so that only one lead with power is on each winding so there's no heat or waste running power through it.