TDP-643R PLUS BAR CODE PRINTER
SERVICE MANUAL
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3.11 Communication (Serial & Parallel Port) Circuit
Fig. 3.11 RS-232 (Serial Port) Circuit
The RS-232 Circuit is for use with the externally connected personal computer
and keyboard unit. JP13 connects to PC serial port through the RS-232 cable.
RxD is the data receive pin of MCU. CTS is the Clear To Send of MCU, which
sends the signal from the external device. TxD is the data output pin of MCU.
RTS is the Request To Send signal which MCU sends to the external device.
The parallel port circuit is for use with the externally connected personal computer
parallel port through the printer cable. When PC‟s strobe signal comes in, the
printer responds the „busy status‟ until it reads the data from parallel port. Printer
will respond the „error signal‟ to PC when it is in error status.
