Compaq 5532 - Manual (Page 133)

Dataproducts Long Line Interface Signals
133
Dataproducts Long Line Interface Signals
Dataproducts-compatible interface signals between the host computer
and the printer are defined as follows:
Data Lines 1 through 8. Provides 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
can enable or disable this line via the Data Bit 8 parameter on the
Dataproducts submenu (see
page 114 ).
Data Strobe. Carries a high true pulse from the host when data is
ready. The data strobe remains high until the Data Request line goes
false. The active edge of the strobe signal can be configured as
leading, middle (default), or trailing.
Paper Instruction (PI). Carries a DVFU signal from the host with the
same timing and polarity as the data lines.
Ready. Carries a high true signal from the printer when AC power and
DC voltages are present, paper is loaded properly, and the printer is not
in a check condition.
Online. Carries a high true signal from the printer when the Ready Line
is true and the ON LINE key on the control panel has been pressed.
When the printer is in online mode, it may accept data from the host.
Demand/Data Request. Carries a high true signal from the printer
when the printer is ready to accept character data from the host. This
signal changes to false shortly after the leading edge of the data strobe
signal.
Cable Verify. Two pins on the interface connector are jumpered
together to allow the user to verify proper installation of the interface
connector.
Buffer Clear. A high true level from the host to indicate the printer
should perform a reboot.
Test. This signal is connected to +5 volts through a 470 ohm resistor.
Parity Error. Always carries a low false signal from the printer
indicating there is no parity error.