130Chapter 5 Centronics Parallel InterfaceCentronics Parallel Interface SignalsData Lines 1 through 8. Provides eight standard or inverted levels from thehost that specify character data, plot data, or a control code. Data Line 8allows access to the extended ASCII character set. You may enable ordisable this line via the Data Bit 8 parameter on the Centronics submenu.Data Strobe. Carries a low true, 100 ns minimum pulse from the host thatclocks data into the printer.Acknowledge. A low true pulse from the printer indicating the character orfunction code has been received and the printer is ready for the next datatransfer.Online. A high true level from the printer to indicate the printer is ready fordata transfer and the ONLINE 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 isin a paper empty or paper jam fault.Busy. A high true level from the printer to indicate the printer cannot receivedata.Prime. A high true level from the host to indicate the printer should perform awarm start (printer is reset to the power-up configuration values).Paper Instruction (PI). Carries a CVFU signal from the host with the sametiming and polarity as the data line.Fault. A low true level from the printer indicates a printer fault.
