Use with two interfaces Interfaces
Programmer Reference Guide U26169-J-Z716-1-7600
© Siemens Nixdorf Informationssysteme AG 1995 Pfad: D:\SNI\Mackwitz\u26169\o26169e\26169e.k11
Use with two interfaces The “Both interfaces active” mode can be selected in the menu (see [2]).
In this mode the printer buffer is subdivided into two parts with 256 bytes ea ch.
After power-on, both interfaces are ready to receive data.
If a byte is received first at the serial interface, the parallel interface is blocked by the BUSY
signal. The serial interface is active and uses the set protocol.
If a byte is received first at the parallel interface, the serial interface is blocked by the DTR
signal (DTR = OFF) or, depending on the protocol, by transmission of XOFF.
A maximum of 256 bytes can be received at the serial interface even though the parallel
interface is active. All further bytes are lost except for the byte received last.
If the printer buffer of the serial interface is completely free and if no further data is received
within 60 seconds, both interfaces are again available.
If the printer buffer of the parallel interface is completely free and if no fur ther data is
received within 60 seconds, the data of the printer buff er of t he serial interf ace is proces sed
and the serial interface is activated.