band and allows transmission rates of up to 54Mbps. 802.11a uses OFDM
(orthogonal frequency division multiplexing) as opposed to FHSS or DSSS.
Higher data rates are possible by combining channels. Due to higher frequency,
range is less than lower frequency systems (i.e., 802.11b and 802.11g) and can
increase the cost of the overall solution because a greater number of access
points may be required. 802.11a is not directly compatible with 802.11b or
802.11g networks. In other words, a user equipped with an 802.11b or 802.11g
radio card will not be able to interface directly to an 802.11a access point.
Multi-mode NICs will solve this problem.
10. What is 802.11g ?
802.11g is an extension to 802.11b. 802.11g increases 802.11b's data rates to
54 Mbps and still utilize the the 2.4 GHz ISM. Modulation is based upon
OFDM (orthogonal frequency division multiplexing) technology. An 802.11b
radio card will interface directly with an 802.11g access point (and vice versa)
at 11 Mbps or lower depending on range. The range at 54 Mbps is less than for
802.11b operating at 11 Mbps.
11. Is it possible to use products from a variety of vendors ?
Yes. As long as the products comply to the same IEEE 802.11 standard. The
Wi-Fi logo is used to define 802.11b compatible products. Wi-Fi5 is a
compatibility standard for 802.11a products running in the 5GHz band.
12. What is Wi-Fi ?
The Wi-Fi logo signifies that a product is interoperable with wireless
networking equipment from other vendors. A Wi-Fi logo product has been
tested and certified by the Wireless Ethernet Compatibility Alliance (WECA).
The Socket Wireless LAN Card is Wi-Fi certified, and that means that it will
work (interoperate) with any brand of Access Point that is also Wi-Fi certified.
13. What types of devices use the 2.4GHz Band ?
Various spread spectrum radio communication applications use the 2.4 GHz
band. This includes WLAN systems (not necessarily of the
type IEEE
802.11b
), cordless phones, wireless medical telemetry equipment and
Bluetooth™ short-range wireless applications, which include connecting
printers to computers and connecting modems or hands-free kits to mobile
phones.
