Teledyne LeCroy BTTracer_Trainer - BTTracer Users Manual - Manual (Page 165)

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BTTracer Protocol Analyzer User’s Manual CATC SW Version 2.20
Acknowledgments are easily seen in BTTracer traces because BTTracer
adds an Ack’d field on data packets of the transmitting device. This means
that you do not have to hunt through the trace to see if the packet was
acknowledged.
The following screenshot shows two examples of Acknowledgments.
Implicit NACK - Packet 14577 is a data packet sent by the piconet Master
device. Packet 14579 should have been a data packet with an
acknowledgment. Instead, it is an empty packet. This Master interprets this
empty packet as an Implicit NACK (i.e., implicitly not acknowledged).
BTTracer summarizes this packet exchange by adding an Ack’d field to the
Master’s data packet and setting the Ack’d field to Imp Nak.
ACK - Packet 14580 is the Master’s retransmission of the data sent in
packet 14577. Packet 14582 is the reply by the Slave device. This reply
contains an ARQN field with a value of (= Acknowledge). BTTracer
summarizes this packet exchange by setting the Ack’d field on packet
14580 to Ack.