So my DAP-2590 went critical nad had a meltdown so I picked up a WAP4410n.
I have a 1522 to bridge some wired devices in my home office an wanted to share what I had to do to ge them to work.
After tons of tweaking and frustration, here is what works best on a wpa2 encrypted 2.4 GHz setup.
Turn off Short GI on the Dlink but leave it auto on the Cisco
Unless you specifically set the channel width (channel bandwidth on Cisco) to 20 Mhz, set the width on the Dlink to Auto 20/40 Mhz
On the Cisco, set the RTS Threshold to 2346. It default to 2347 and the Dlink has a max of 2346. this was my key to success. Once I set this and turned off short GI on the Dlink, I have had a stable and strong connection.
Hope this wilol help someone. The RTS Threshold issue may affect multiple APs or routers and might be an important tip.