Centronics Interface Signals
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Centronics Interface Signals
The Centronics interface signals between the host computer a nd the printer
are defined as follows:
Data Lines 1 through 8. Provide eight standard or inverted levels from the
host that specify a character or function 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.
Data Strobe. Carries a low true, 100 ns min. pulse from the host that clocks
data into the printer.
Paper Instruction (PI). Carries a VFU control signal from the host with the
same timing as the data lines.
Acknowledge. A low true pulse from the printer indicating the character or
function code has been received and the printer is ready for the n ext data
transfer.
Online. A high true level from the printer to indicate the printer is ready fo r
data transfer and the ON LINE key on the operator panel has been activated.
When the printer is in online mode, it may accept data fr om the host.
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.
Centronics Parallel Interface Configuration
Your printer is configured at the factory to match the int erface you specified.
By using the operator panel, you may verify and chang e several interface
parameters in order to meet specific application requireme nts.
Refer to “Centronics (Parallel) Submenu” on page 117 for Centron ics
parameter descriptions and information on selecting values for the following
parameters:
•Data Bit 8 (enable or disable)
•Data Polarity (standard or inverted)
•Strobe Polarity (standard or inverted)
•Response Polarity (standard or inverted)
•Busy on Strobe (enable or disable)
•Latch Data On Leading or Trailing Edge of Strobe
•Prime Signal (enable or disable)
•TOF Action at Prime Signal (do nothing or form feed)
•I/O Buffer Size (1-6)
Some application programs require a unique configur ation. If the printer is not
working properly in the configuration you have sele cted, contact an
authorized Printronix representative.