Is a PhiHong Midspan unit basically a switch/hub unit so that you can put it between a router and a set of phones? Or are they just power injection units essentially amalgamating 8, 16 or 24 channels where you have an in/out for each cable from the router on it’s way to the phone? Or something else….?
They are not a switch. They do nothing with the data. You still need a switch port to connect each power port to.
For each powered port they have an in and out socket.
in = data only to connect to the switch or router.
out = power and data to connect to IP phone or other Poe device.
When you are using the 8,16 or 24 port version you would usually need a set of short patch cables to connect all the in ports to the switch.
So why not just buy a POE switch?
1) The Size. The Midspans aren’t very deep so will fit into most networking cabinets. Many PoE Switches are full depth devices
2) To power an existing switch: If you have already made an investment in switches, you can add power without throwing away your existing switches. For many high end managed switches, separate power using a Midspan can be cheaper than a powered PoE switch to the same specification.
3) if you just want to power some ports.