iDP3420/3421/3423 User’sMa nual
28 CITIZEN
9.3 Input and Output Signals9.3.1 Inputand Output Signals(1) Input signals to the printer
•DATA : An 8-bit parallel signal. (Positive logic)
•STB : A strobe s ignal to read the 8 -bit data. (N egative logic)
•RESET : A signal to reset the printer from the outside. (Negative logic)
(2) Output signals fr om 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 i ndicate the BUSY s tatus of the pri nter. Input new data when a t
"LOW". (Positive logic)
•FAULT : A signal turned to "LOW" whe n the printer has an alarm. At this t ime, all the
controlcircuitsin the printer stop. (Negative logic)
•SELECT : A signal to show wheth erthe printer is s elected (On-line) or deselected.
(Positivelogic)
•COMPULSION
: A signa l to show the status of the d rawer switch. (Positive logic)
•PE : A signal to show that the paper has run out. Normal at the "LOW" level, but
turnedto the "HIGH" level when th e paper has run out.
(3) Powerrelated signal
•GND : Common ground on the cir cuits
•Vcc : A +5 V si gnal. Connected via a 3.3k Ωresistor.