User`s guide

9XTend™ RS-232/422/485 RF Modem User’s Guide
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3.2.3. Receive Mode
If a modem detects RF data while operating in Idle Mode, the modem transitions to Receive Mode
to start receiving RF packets. Once a packet is received, the modem checks the CRC (cyclic redun-
dancy check) to ensure that the data was transmitted without error. If the CRC data bits on the
incoming packet are invalid, the packet is discarded. If the CRC is valid, the packet proceeds to the
DO Buffer.
Figure 3-06. Receive Mode Data Flow
* Refer to the ‘Address Recognition’ sec-
tion for more information regarding
address recognition.
The modem returns to Idle Mode
when valid RF data is no longer
detected or after an error is
detected in the received RF data. If
serial data is stored in the DI
buffer while the modem is in
Receive Mode, the serial data will
be transmitted after the modem is
finished receiving data and returns
to Idle Mode.