Dear @Sugar_Rush,

EAP225-Outdoor support 2.4Ghz. So I want to use EAP225-Outdoor like this

Any Wireless Internet)))   (((EAP225 -> PoE -> router -> computer 

So is that possible to set a system like this? 

I'm afraid that EAP225-Outdoor cannot work like that. EAP225-Outdoor is just an access point, which is required to be hardwired to the Internet via cable.

I have CPE520 products. (Lower than 25dbm. Our country didn't allow over 25dbm. CPE220 support 2.4Ghz but that is over 25dbm) 

CPE520 support only 5Ghz. I use CPE520 Client mode like this.  

Any Wireless Internet)))   (((CPE520(client mode) -> PoE -> router -> computer 

For your concern, may I ask why you need a 2.4GHz device? Is the Wireless Internet providing 2.4GHz or 5GHz, or both? Do you have any issues with the 5GHz CPE520?

Please kindly note that the CPE520 in Client mode doesn't broadcast 5GHz WiFi, but only pick up the WiFi signal from the Wireless Internet and then feed the Internet to the behind router (or AP) via Ethernet cable. If your demand is to receive 2.4GHz WiFi on the computer, you could add the EAP225-Outdoor to make it, so the setup is like this:

Wireless Internet )))5GHz((( CPE520(client mode) ----- router ----- EAP225-Outdoor )))2.4G&5G((( computer or other wireless clients

Note: in the setup above, the router can be removed according to your actual requirements as it's not a must.