I have a previous generation (white) iMac which has the software update for 802.11n. I am now going to buy a Time Capsule to back up both the above iMac and a new aluminium one and then use my current AEBS to set up a separate "g" network for other devices (iPhones). The documentation I've seen talks about creating a 5GHz network for "n' machines and a 2.4GHz network for others. I don't know, however, if the older iMac is capable of 2.4GHz only, or if it can run at 5GHz. If it can't, it seems pointless to create the dual-band network. Appreciate any responses.