Centronics Interface Signals; Centronics Parallel Interface Configuration - Printronix 9012 User's Reference Manual

second. The maximum data line length (cable length) from the controller (host com
puter) to the printer is 40 feet.

Centronics Interface Signals

Table 7-3 lists the Centronics interface connector pin assignments. Centronics interface
signals between the computer and the printer are defined as follows.
PE - A high true level from the printer to indicate the printer is in a check condition.
SLCT - A high true level from the printer to indicate the printer is ready for data trans
fer and the ON LINE switch has been activated.
Busy - A high true level from the printer to indicate the printer cannot receive data.
ACKNLG - 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 min. pulse from the host to clock data into the printer.
Data Lines - Eight standard or inverted levels from the host that specify a character or
function code. Sensing Data Line 8 is controlled by printer configuration.
Paper Instruction (PI) - Optional EVFU control signal from the host with the same tim
ing and polarity as the data lines. Sensing the PI line is controlled by printer configura
tion.
NOTE: The PI Line must be disabled (configuration option selected from
the front 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 paper
slewing will occur.

Centronics Parallel Interface Configuration

The printer is configured at the factory. However, the configuration is also user selec
table. The following configuration parameters can be verified or changed as necessary to
meet specific application requirements:
Input Buffer Size (Selected from the Application Compatibility Menu)
Data Bit 8 (Enable or Disable)
PI Line (Enable or Disable)
Data Polarity
Response Polarity (standard or inverted response)
Latch Data On Leading or Trailing Edge of Strobe
Fast Busy (Enable or Disable)
These parameters are displayed under the Application Compatibility/Host Interface/
Centronics submenu selectable from the control panel. Refer to the Control Panel Con
figuration Diagram in the Configuration chapter for information on selecting the
various parameter values.
7-4 P9012 Interfaces