PORTABLE INPUT/OUTPUT DEVICE

摘要

PURPOSE:To ensure the succession of the working of a printer by using a circuit which cuts off the alarm signal for drop of the power supply voltage when the printer is working and therefore preventing the generation of an alarm due to the temporary drop of the power supply voltage at working of the printer. CONSTITUTION:A motor is started for a printer 24 when an MSTA signal 23 produced from a motor control part of a printer control part 21 is set at an active high level. The signal 23 is kept at a low level while the printer 24 is kept inactive. Thus an ALM signal 28 is produced with the drop of the power supply voltage and set at a high level. Then the signal 28 is transmitted to a main control part 2B through an AND gate 2A. While the signal 23 becomes an active high level when the printer 24 is active. Thus the produced signal 28 is set at a high level but does not pass through the gate 2A. Therefore the signal 28 is not sent to a main control part 2B. This fact shows that the signal 28 is not cut while the printer 24 is working.