iDP3420/3421/3423 User’s Manual
28 CITIZEN
9.3 Input and Output Signals
9.3.1 Input and Output Signals
(1) Input signals to the printer
• DATA : An 8-bit parallel signal. (Positive logic)
• STB : A strobe signal to read the 8-bit data. (Negative logic)
• RESET : A signal to reset the printer from the outside. (Negative logic)
(2) Output signals from the printer
• ACK : An 8-bit data request signal. A pulse signal output at the end of the BUSY signal.
(Negative logic)
• BUSY : A signal to indicate the BUSY status of the printer. Input new data when at
"LOW". (Positive logic)
• FAULT : A signal turned to "LOW" when the printer has an alarm. At this time, all the
control circuits in the printer stop. (Negative logic)
• SELECT : A signal to show whether the printer is selected (On-line) or deselected.
(Positive logic)
• COMPULSION
: A signal to show the status of the drawer switch. (Positive logic)
• PE : A signal to show that the paper has run out. Normal at the "LOW" level, but
turned to the "HIGH" level when the paper has run out.
(3) Power related signal
• GND : Common ground on the circuits
• Vcc : A +5 V signal. Connected via a 3.3k Ω resistor.
