C.3. RS-232C/RS-422A Protocol

H5: Protocol logic

Parameter value

Meaning

0

Combination of 1 and 3 below

 

 

1

DTR/DSR, positive logic

 

 

2

DTR/DSR, negative logic

 

 

3

XON/XOFF

 

 

4

ETX/ACK

 

 

5

XON/XOFF recognized only as protocol

 

 

The factory setting is 0.

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.

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 IIe FRPO D0 command

The PRESCRIBE IIe 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

XON sent every 3-5 seconds

D0

= 0 (default)

D0 = 1

host while Ready or Waiting

XON not sent

D0

= 10

D0 = 11

 

 

 

 

 

 

C-11

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Kyocera FS-1700 user manual Prescribe IIe Frpo D0 command, Serial interface error, Error not handled Error handled