Wireless USB and PCMCIA (PC Card) adapters now available are very similar in performance. There is little reason, other than personal preference to choose one over the other. There is good reason to choose a laptop with a built-in Wi-Fi adapter over an external option, so if you’re considering saving a few dollars by getting a USB or PC Card adapter instead - don’t.

Wireless range is directly related to the amount of power sent through the antenna. Since laptop devices usually have less powerful antennas than base stations plugged into the wall, early reports of inferior range in USB wireless devices were because the USB bus supplied less power (ref. #1 below) than the PC Card bus (ref. #2 below). Now that the antennas on both types of devices are very similar and most Windows XP drivers allow Windows to manage the power used by the wireless device automatically it’s rare for either USB or PC Card devices to either be run at full power or for one type to have a better range than the other.

An internal wi-fi card is a big improvement over the above options, because the antenna are much larger and more sensitive. Most laptops with internal wireless devices have an antenna wire in around the outside edge of the screen, making a big improvement over any external options, regardless of power output.

Also, PC Card technology has more power-saving modes (handled automatically by the PC Card controller, ref. #2 below) than USB does. Before Windows XP started to manage power via the driver - PC Card wireless devices went into low-power mode more often and depleted the battery less than USB devices did. Now there is little to no noticable difference in battery use by either device. …although, when a laptop is put to sleep either device will continue to consume a small amount of battery power if it is left in the laptop. Since USB has slightly better hot-plug support (ie: it can be removed and reinserted without causing errors on the PC) it is usually easier to remove it when putting the PC to sleep. …so, maybe USB is the way to go for you.

Note on Wireless-B, -G, and -N: It’s worth paying attention to the type of communication that a wireless device uses. All Wi-Fi devices “speak” some form of the 802.11 “language”. The letter after the 802.11 indicates the “flavor” of the language - and some are much better/faster than the other flavors. 802.11G deals with radio “noise” (like microwaves and cordless phones) better than 802.11B. Also, if you can find a “pre-N” (pre-802.11N) wireless device choose it (if it’s in your budget). The pre-N technology may not work with the final 802.11N, but all N-flavor devices have much better antennas than the B or G flavors. So, the “best” flavor is “pre-N”, followed by “G”, and then by “B”.

References:

1. http://www.usb-port.com/usb_faq.html - USB supplies 500mA @ 5V
2. http://www.pcmcia.org/pccard.htm - PC Card supplies 660mA @ 5V, 1000mA @ 3.3V

One Response to “Choosing External Wi-Fi Adapters for Laptops - USB vs. PCMCIA”

1. PAT, on March 2nd, 2007 at 10:00 am, said:
   

   THANKS MAN!!!

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