Mac users with 802.11n-capable hardware who want to take advantage of the wireless technology will have to pay $1.99 for enabler software that lets them use fast Wi-Fi.

In last week's Macworld Expo Apple introduced a new AirPort Extreme wireless networking base station that supports a draft of the IEEE's forthcoming 802.11n fast Wi-Wi standard. This should give better speed and range with any Wi-Fi client, but will only give draft-N performance - five times that of 802.11g, and double the range - when used with Draft-N equipped clients.

Apple has been shipping Macs that are capable of Draft-N for some months, although the standard is still not complete. These machines need a software upgrade before they can use Draft-N. The update is included on the install CD of the new base station, but those wanting to use Macs with other APs (such as the of Netgear DG834N, Linksys WRT300N, Belkin N1, D-Link Rangebooster N650 and Buffalo Airstation Nfiniti). have to download it for a $1.99 fee.

The enabler software works with Intel Core 2 Duo and Intel Xeon-equipped Macs (except the entry-level 1.83GHz, 17 in iMac) so that they support the draft specification of the IEEE 802.11n wireless networking standard.

The fee is an accounting requirement, according to Apple. "The nominal distribution fee for the 802.11n software is required in order for Apple to comply with generally accepted accounting principles for revenue recognition, which generally require that we charge for significant feature enhancements, such as 802.11n, when added to previously purchased products," said Teresa Brewer, Apple's Mac hardware public relations manager. Earlier rumours suggested the fee would be as much as $5.

Eventually, all new Macs will be shipped with the 802.11n software included, Brewer added.