Citizen iDP-3535, Service Manual, Page: 22 / 37

iDP-3535 Service Manual
CITIZEN
22
8. Serial Interface Circuit (3535R-type only)
1) Transmitting and Receiving Circuits (RS-232C)
Data receiving (RD), BUSY (DTR), and FAULT signals are transmitted and received by a RS-232C
transmitter of IC9 (MAX232C). RD signals are controlled by PC1 of IC1, FAULT signals by PC0 of IC!,
and DTR signals by PC2 of IC1 respectively.
2) Reading of Dip Switch
DS2 (Dip switch) is composed of eight switches, and reads with PD0 to PD7. Setting the dip switch
enables baud rate (110 to 9600 bps), word length, parity check, and parity condition setting.
3) Positive and negative voltage for RS232C
A power supply of +12V is required to maintain the voltage level of RS-232C.
Since this printer pr12V voltage with a power supply circuit built in the IC, a separate +12V
power supply is not required.
Fig. 8-1 Serial Interface Circuit