Printronix L5520 - Manual (Page 229)

Dataproducts Parallel Interface
229
Dataproducts Parallel Interface Signals
The Dataproducts interface signals are defined below:
• READY - A high true signal from the printer indicating AC
power and DC voltages are present, paper is loaded properly,
and the printer is not in a fault condition.
• ON LINE - A high true signal from the printer indicating the
Ready Line is true and the ONLINE key on the control panel
has been activated. The printer is ready to accept data from the
host.
• DATA REQUEST - A high true signal from the printer to
synchronize host data transmission with printer timing. This
signal goes true when the printer is ready to receive data. It
changes to the false state shortly after the leading edge of the
data strobe signal.
• DATA STROBE - A high true pulse from the host to indicate
that data is ready. The data strobe must remain high at least
until the Data Request line goes false.
• DATA LINES - Eight standard or inverted levels from the host
that specify character data, plot data, or a control code.
Sensing Data Line 8 is controlled by printer configuration.
• PAPER INST - Optional standard or inverted level VFU control
signal from the host with the same timing and polarity as the
data lines. Sensing of the PAPER INST line (PI line) is
controlled by printer configuration.
NOTE: The PAPER INST line must be disabled (configuration
option selected from the control panel) if the host computer
does not drive or control it. If the line is not controlled by the
host and PAPER INST line sensing is enabled in the
printer, rapid paper slewing occurs.
• Interface Verification - Two pins on the interface connector
jumpered together allow you to verify proper installation of the
interface connector.