Centronics Parallel Interface Signals - Printronix P9212 Setup Manual

Centronics Parallel Interface Signals

Table 4–2 lists the Centronics interface connector pin assignments.
Centronics-compatible interface signals between the computer and the printer
are defined as follows:
Data Lines 1 through 8 — Eight standard or inverted levels from the host
that specify a character or function code. Sensing Data Line 8 is controlled
by printer configuration.
Data Strobe — A low true, 100 ns min. pulse from the host that clocks data
into the printer.
Paper Instruction (PI) — Optional EVFU or DVFU control signal from the
host with the same timing as the data lines. Sensing the PI line is controlled
by printer configuration.
NOTE: The PI line must be disabled (a configuration option selected from
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.
Online — A high true level from the printer to indicate the printer is ready
for data transfer and the ONLINE key has been activated.
Paper Empty (PE) — A high true level from the printer to indicate the
printer is in a fault condition.
Busy — A high true level from the printer to indicate the printer cannot
receive data.
Printer Interfaces
the control panel) if the host computer does not drive or control the
PI line. If the line is not controlled by the host, and sensing is
enabled, rapid vertical paper movement ("slewing") will occur.
4–7