Printronix ProLine 5 Series Manual page 183

Centronics Interface Signals
Data Lines 1 through 8 — Provide eight standard or inverted levels from the
host that specify character data, plot data, or a control code. Data Line 8 allows
access to the extended ASCII character set. You may enable or disable this line
via the Data Bit 8 parameter on the Centronics submenu (see Chapter 4).
Data Strobe — Carries a low true, 100 ns minimum pulse from the host that
clocks data into the printer.
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 ON LINE key on the control panel has been activated. When the
printer is in online mode, it may accept data from the host.
Paper Empty (PE) — A high true level from the printer to indicate the printer is in
a paper empty or paper jam fault.
Busy — A high true level from the printer to indicate the printer cannot receive
data.
Prime — A high true level from the host to indicate the printer should perform a
warm start (printer is reset to the power–up configuration values).
Paper Instruction (PI) – Carries a CVFU signal from the host with the same
timing and polarity as the data line.
Fault — A low true level from the printer indicates a printer fault.
5–8 Interfaces