User's Manual

CDR-915L OEM DATA RADIO MODULE
___________________________________________________________________________________________
Revision M INTEGRATOR’S GUIDE
20
CDR-915L D ATA R ADIO
H ARDWARE TIMING
Ack-Back™ Handshaking
When configured for Ack-Back™ mode, the radio will attempt to resend packets that are not acknowledged as
received by the destination radio. While this virtually guarantees that data will be correctly transmitted, there is still
the possibility that the destination radio is unavailable. Because of this, the CDR-915 supplies hardware indication
of the success or failure of Ack-Back™ packets. (See Radio Hardware Interface for pin definitions)
Shown below is an example of the hardware handshaking for a successful Ack-Back™ transmission. The TX trace
identifies the actual transmission attempt and is internal to the radio. The SNDING trace is the handshake signal on
Pin 9 of P2. This signal goes high when the transmit attempt is made and stays high until the acknowledgement
packet is received from the destination radio.
Successful Ack-Back Transmission