http://www.macnn.com/articles/09/10/27/usb.adapter.supports.80211a.b.g.n/
QuickerTek brings 802.11a to older Macs
updated 04:55 pm EDT, Tue October 27, 2009
USB adapter supports 802.11a/b/g/n
QuickerTek has released a new USB wireless adapter which adds Wi-Fi support to any Mac with a USB port. The device handles 802.11a connections running at 5.8GHz, and 802.11b/g/n networks operating at 2.4GHz. 802.11a, notably allows connnection speeds up to 300Mbps.
All of Apple's AirPort routers are supported, as well as most other 802.11-based devices. Buyers can find the adapter on the QuickerTek website at a cost of $100; included is a one-year warranty for parts and labor. Mac OS X 10.4 or later is required.
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Joined: Jun 2000
Wrong technical info.
This article, and their site, is wrong. They have their 802.11a and 802.11n backwards. 802.11a is 54 Mbps on the 5 GHz band, 802.11n is up to 300 Mbps on the 5 Ghz band (802.11n can also operate on the 2.4 GHz band like 802.11b and 802.11g, but not sure what the max speed there is. Neither operates at the 5.8 GHz as mentioned in the article.