Do all 802.11b/g access points use Time Division Duplex
I suspect confusion caused by acronym reuse. In my earlier answer, I referred to Time Division Duplexing (TDD) as a generic term describing duplex methods that allow devices to transmit and receive on a single frequency at different intervals. 802.11a, b, and g standards operate in this fashion, letting many stations share a single radio channel by using a coordination function to transmit when that channel is free. However, you won't find the term "TDD" in the 802.11 standard. Furthermore, this acronym is often used to specific wireless WAN services like WCDMA TDD or TD-CDMA. And, no, 802.11 products do not implement WCDMA TDD – they are entirely different wireless standards. To learn more about TDD, download this TDD Coaltion tutorial. By the way, TDD also stands for Telecommunications Device for the Deaf and the airport in Trinidad, Bolivia!