Wireless Networking Cards buying guide
Generally, unless your walls are plaster or wood, it is best to buy about four times the force you think you need. Even in perfect conditions, you get twice as much as you think you need - just to be safe.
You probably noticed in the specifications above, the number 802.11, followed by a letter b. The b is the standard that the wireless device is also compliant. Currently, there are three standards - a, b and g.
In short, 802.11b and 802.11g are compatible, while 802.11a is not compatible with either. Due to incompatibility issues with the other two standards, and because it is an old standard less robust than it should stay away from the cards to use.
Between b and g, b are cheaper, but more slowly, while g is more expensive but faster. It is also interesting to consider the addition of a state device B to a network that ag-speed devices often will slow the entire network down to b-flow, which makes sense g-unit . Basically, the network will operate at the speed of its weakest link.
If the wireless device does not respond to standard right, will not be very good to you. I often see people ignorant of offers on eBay to use wireless devices, without realizing that it will be painfully slow, and not necessarily with other devices, they could have. Always check that the standard for wireless devices to use and do not know if the letter of 802.11, do not buy it!