Microplex PP 404, Руководство пользователя

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B-4
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 characters. 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 immediately 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.