Scanning Issues for a Device in Inquiry Scan State
Original Post: Inquiry Scan state question (eGroups Msg. )
Date: 2000-01-05
Question
When a BT device enters Inquiry Scan mode, the
spec (1.0A) says it will listen for a minimum of 18 slots at a given
frequency. Does this mean that the device will listen in both its TX and
RX slot times? Or does it use a mechanism like the HOLD extension of the
uncertainty period from +- 10uS to a larger number, say +-1250uS?
Answer
The TX and RX slots are determined by the master's
clock. A device entering Inquiry scan has no knowledge of the master's
clock. So the concept of TX and RX slots does not apply to a device in
Inquiry scan. It scans continuously for 16 hop frequencies (not 18) and
when it receives an inquiry message, it performs the inquiry response
procedure. A device sending the inquiry message (master) however transmits
only in transmit slot and listens in receive slots. These slots are
determined by it's native clock. There is no extension of the uncertainty
period
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