C.3. RS-232C/RS-422A Protocol
C-10
H6: Buffer nearly-full threshold
This is a percentage from 0 to 99. The factory setting is 90.
H7: Buffer nearly-empty threshold
This is a percentage from 0 to 99. The factory setting is 70.
The factory settings of the buffer nearly-full and nearly-empty thresholds (H6 and H7) are
subject to change without notification.
The gap between the nearly-full and nearly-empty thresholds allows the computer to send
a fairly large amount of data in a continuous stream.
H8: Received-data buffer size
This is the size of the input buffer, specified in units of 10K bytes. The factory-set value is 6
meaning 60K bytes.
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Since DTR/DSR protocol is not used with the RS-422A standard, select a parameter
value other than 0, 1, or 2 for the H5 setting when using the RS-422A interface.
PRESCRIBE 2e FRPO D0 command
The PRESCRIBE 2e FRPO D0 command is provided to allow manipulating XON/XOFF
when an error has occured on the serial interface. The following table summarizes the error
status corresponding to different D0 values.
Serial interface error
error not handled
error handled
Timing of XON transfer to
host while Ready or Waiting
XON sent every 3-5 seconds D0 = 0 (default)
D0 = 1
XON not sent
D0 = 10
D0 = 11
