Receive Mode - HORNER HE200WCM910 User Manual

RS‐232/485 RF Modem Product Manual – MAN0782‐02

Receive Mode

CRC (Cyclic Redundancy Check)
To verify data integrity and provide built-in error checking, a 16-bit CRC (Cyclic Redundancy
Check) is computed for the transmitted data and attached to the end of each RF packet before
transmission. On the receiving end, the receiving modem computes the CRC on all incoming RF
data. Received data that has an invalid CRC is discarded. [See Receive Mode section, next
section.]
If a modem detects RF data while in Idle Mode, the modem transitions into Receive Mode to start
receiving RF packets. Once a packet is received, it goes through the receiving end of a CRC
(cyclic redundancy 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 is
placed the DO Buffer.
Figure 3.7. Receive Mode Data Flow
* Refer to the Addressing Options section (under the RF Communication Options chapter) for more
information about address recognition.
The modem returns to Idle Mode after valid RF data is no longer detected or after an error is
detected within 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.
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