Epson 8900 Series - Manual (Page 25)

Printer Setup 2-12
XON/XOFF (transmit-on/transmit-off)
For this busy-handling protocol, the printer sends a single XON (a
DC1 control character) to indicate that it is ready to receive data and
a single XOFF (a DC3 control character) to indicate that it is busy.
The default setting is OFF.
Robust XON/XOFF
For the robust XON/XOFF protocol, the printer sends an XON (DC1
control character) approximately every 5 seconds to indicate that it is
ready to receive data until either data is received or another busy
condition occurs. The printer sends an XOFF (DC3 control character)
when the initial busy condition occurs (buffer overflow) to indicate
that it is busy. If the host continues to send data, the printer sends an
XOFF approximately every 20 ms until the hosts stops sending data.
The default setting is OFF.
The following table lists the ready and busy points using the
XON/XOFF protocol.
LCD Display of Busy Point Ready Point
Buffer Size From Empty After Busy
32,000 @ 32,000 Bytes @ 31,250 Bytes
4,000 @ 4,000 Bytes @ 3,250 Bytes
256 @ 256 Bytes @ 128 Bytes
Note: Actual buffer size is 32,768 bytes; overflow error status only
occurs after 32,768 bytes.