Bluetooth 1.1
Ratified as IEEE Standard 802.15.1-2002.
Many errors found in the 1.0B specifications were fixed.
Added support for non-encrypted channels.
Received Signal Strength Indicator (RSSI).
Bluetooth 1.2
This version is backward-compatible with 1.1 and the major enhancements include the following:
Faster Connection and Discovery
Adaptive frequency-hopping spread spectrum (AFH), which improves resistance to radio frequency interference by avoiding the use of crowded frequencies in the hopping sequence.
Higher transmission speeds in practice, up to 721 kbit/s, as in 1.1.
Extended Synchronous Connections (eSCO), which improve voice quality of audio links by allowing retransmissions of corrupted packets, and may optionally increase audio latency to provide better support for concurrent data transfer.
Host Controller Interface (HCI) support for three-wire UART.
Ratified as IEEE Standard 802.15.1-2005.