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Communications (Serial and Parallel)
16.2
Communication Settings
423. Stop Bit
Select the number of stop bits in each byte (either 1 or 2).
424. Parity
Select the type of parity checking to use to check the data. The selection
options are None, Odd, or Even.
425. Flow Control
Set the method of handshake flow control. The selection options are
None or Xon/Xoff.
Point
What is flow control?
During high−speed serial communication, overflow can occur if the receiving
device's processing speed cannot keep up with the sending device's
transmission speed. Flow control is used to prevent this.
There are two types of flow control: soft flow and hard flow. Soft flow controls
the data flow using an XON/XOFF code embedded in the transmitted data,
while hard control uses the RTS/CTS signal. Generally, soft flow is used
when the transmitted data contains only text, and hard flow is used for
binary data.
However, neither type of flow control can completely prevent all errors, and
overflows may also be generated due to processing on the computer side.
If this happens, either switch to a faster computer, or decrease the baud rate
(communication speed).
16 − 10
OCR Type A230
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