Hi;

Can 2830n roam wireless devices with others wireless AP/routers from differents vendors..like apple Extreme. and how to set it up.

Many thanks.

If you want to use roaming:
make the ssid + password + encryption identical in all APs - but use channels which dont overlap, that should be enough. The client is however resonsible to do the actual roaming.

If you want to use WDS (using the AP as a repeater/bridge and accesspoint to enlarge the range of the Wireless network):
The 2830 supports WDS, so this should be possible also. However, even if WDS is a standard somtimes the setup is easier if you use identical hardware.