80211b

802.11b is an amendment to the IEEE 802.11 family that defines a wireless local area network (WLAN) operating in the 2.4 GHz ISM band. Ratified in 1999, it increases the data rate of the original 802.11 PHY while preserving backward compatibility with earlier 802.11 devices. 802.11b uses Direct Sequence Spread Spectrum (DSSS) with Complementary Code Keying (CCK) modulation to achieve higher throughput.

The standard supports four data rates: 1 Mbps and 2 Mbps using DSSS, and 5.5 Mbps and 11 Mbps using CCK. In typical deployments, the higher rates are used within shorter ranges or in environments with less interference, while the lower rates provide more robust connections at greater distances.

802.11b operates in the 2.4 GHz band, which is shared with many other technologies and devices. The band is divided into channels with a 22 MHz bandwidth; in many regions there are up to 11 channels, with non-overlapping use commonly achieved on channels 1, 6 and 11. Actual performance is heavily influenced by environmental factors such as walls, furniture, interference from microwaves, Bluetooth devices, and other 2.4 GHz equipment.

Security for early 802.11b networks often relied on WEP, which later proved insecure and was supplanted by WPA and WPA2 in newer equipment. 802.11b played a pivotal role in the early adoption of Wi‑Fi, and it influenced subsequent standards such as 802.11g, which offered higher data rates in the same 2.4 GHz band. Some 802.11b devices remain in use in legacy or cost-sensitive deployments.