Centronics Parallel Interface Signals - Printronix L5000 Series Maintenance Manual

Centronics Parallel Interface Signals

The Centronics interface signals are defined below.
PAPER EMPTY – A high true level from the printer to indicate the printer is in a
fault condition.
SELECT – A high true level from the printer to indicate the printer is ready for data
transfer and the ON LINE key has been activated.
BUSY – A high true level from the printer to indicate the printer cannot receive data.
ACKNOWLEDGE – A low true pulse from the printer indicating the character or
function code has been received and the printer is ready for the next data transfer.
DATA STROBE – A low true, 100 ns minimum pulse from the host to clock data
into the printer.
DATA LINES – Eight standard or inverted levels from the host that define the data,
which may consist of a character or function code. Sensing Data Line 8 is controlled
by printer configuration.
PAPER INST – Optional VFU control signal from the host with the same timing and
polarity as the data lines. PI line sensing is controlled by printer configuration.
PRIME – Optional low true signal from the host used to reset the printer to its
default power–up state.
FAULT – Reserved for future use.
NOTE: The PAPER INST line must be disabled (configuration option selected from
Host I/O Interfaces
the front panel) if the host does not drive or control it. If the line is not
controlled by the host and sensing is enabled, rapid paper slewing will
occur.
F–7