Kyocera FS 1900 Operation Guide - Page 210

RS-232C/RS-422A Protocol H5: Protocol logic Parameter value 0 1 2 3 4 5 Meaning Combination of 1 and 3 below DTR/DSR, positive logic DTR/DSR, negative logic XON/XOFF ETX/ACK 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 10 Kbytes. The factory-set value is 6, meaning 60 Kbytes. 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 Note RS-422A interface. PRESCRIBE FRPO D0 Command The PRESCRIBE FRPO D0 command provides control over XON/XOFF operation when an error occurs on the serial interface. The following table summarizes the error status corresponding to different D0 values. Timing of XON transfer to host while Ready or Waiting XON sent every 3-5 seconds XON not sent Serial interface error Error not handled Error handled D0=0 (default) D0=1 D0=10 D0=11 C-10