Additional Information - PSI Matrix PP 404 Benutzerhandbuch

Appendix B System Interface Description
B.3

Additional Information

After Power-ON DTR and RTS are activated and the printer is ready to receive
data.
XOFF is sent, when the interface buffer has only space left for 256 more charac-
ters. XOFF is sent again, at a level of 128 characters buffer space. Further
incoming data will be stored until the interface buffer is full. All data sent in
addition will get lost.
XON is sent when the interface buffer provides space for a minimum of 512
characters.
XON/XOFF can only be sent successfully when CTS is at active state.
When the CTS Mode is set to "CTS ignore" CTS is always in the active state.
XOFF will be sent immediately if local mode is entered.
XON is sent again, if local mode is left and a minimum of 512 byte interface
buffer is available.
Shared Operation
In shared operation the interface buffer capacity is reduced by 256 bytes.
After Power-ON both the serial and the parallel interfaces are available for data
transfer.
If a byte is first recognized by the serial interface, the parallel interface is imme-
diately disabled by the BUSY signal. The serial interface is now active and will
operate, using the installed protocols.
If a byte is first recognized by the parallel interface either the DTR signal of the
serial interface is set to OFF or XOFF is sent, depending on the protocol.
B-4