with 1.1. The main enhancement is the introduction of an Enhanced Data
Rate (EDR) for both data (ACL) and voice (eSCO) packets. The nominal
signalling rate of EDR is about 3 megabits per second, although the
practical data transfer rate is 2.1 megabits per second.[8] This
additional throughput is obtained by using a different modulation
scheme for radio transmission of the data payload. Standard or Basic
Rate transmission uses the Gaussian Frequency Shift Keying (GFSK)
method, while EDR uses a combination of GFSK and Phase Shift Keying
(PSK).
According to the 2.0 specification, EDR provides the following benefits:
* Three times faster transmission speed — up to 10 times in
certain cases (up to 2.1 Mbit/s).
* Lower power consumption through a reduced duty cycle.
* Simplification of multi-link scenarios due to more available bandwidth.
The Bluetooth Special Interest Group (SIG) published the specification
as "Bluetooth 2.0 + EDR" which implies that EDR is an optional
feature. In some cases it is not clear whether a product claiming to
support "Bluetooth 2.0" actually supports the EDR higher transfer
rate. At least one commercial device, the HTC TyTN pocket PC phone,
states "Bluetooth 2.0 without EDR" on its data sheet.
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