Unisys E-@CTION EFP9800 - Manual (Page 83)

Communication
3255 4073–002 5–3
•
For XON/XOFF, a particular character is sent back and forth between the
host computer and the printer to regulate the communication.
•
For DTR/DSR, changes in the DTR/DSR signal coordinate the information
flow.
The RS-232C version of the EFP9800 offers the standard options which are
selected with the DIP switches. For more information on these settings, see
“Setting Switches” later in this section.
XON/XOFF Protocol
The XON/XOFF characters coordinate the information transfer between the
printer and the host computer. The printer sends an XON character when it is
ready to receive data and it sends an XOFF character when it cannot accept any
more data. The software on the host computer must monitor the
communication link as shown in the following flowchart in order to send data
at appropriate times.