IEEE 802.11b specifies the operation of local wireless networks in the ISM frequency band (Industrial, Scientific, Medical: 2.4 to 2.483 GHz). Maximum datarates are up to 11 Mbps. Actual throughput depends on the distance and the quality of the connection. With longer distances and lower connection quality datarates sink to 5.5 Mbps, thereafter to 2 Mbps and then to 1 Mbps. The range of transmission in the open can reach up to 150 m. Inside of buildings this would typically be 30 m. IEEE 802.11b is not compatible to IEEE 802.11a as they operate at different frequencies.
To protect against interference from other transmitters operating on the same frequency, the 2.4-GHz frequency band for IEEE 802.11b offers the DSSS procedure (Direct Sequence Spread Spectrum). Generally, a transmitter occupies only a very narrow band of the available frequencies. If this band is also being used by another transmitter, interference may occur. The DSSS method uses a broader band of the available frequency range, making it less sensitive to narrow-band interference.