Olympus OEP-3, Service Manual

Page: 153 / 176

4-45
OEP-3 V1 (UC)
4-4-4. RS Communication Control
RS-232C interface
A signal is converted from serial to parallel by IC250 (uPD71051GU) that is connected to CPU via a bus.
Input and output signals are level-converted by IC280 and IC281 (SP232CAN).
The last output signal is as follows:
Active: 8 V
Non-active:
_
8 V
The TP position is as follows:
Active:
0 V
Non-active:
+
5 V
Signal line name I/O Description
TXD Output Communication data (UP
→
External)
RXD Input Communication data (External
→
UP)
RTS Output Communication enable (UP
→
External)
CTS Input Communication enable (External
→
UP)
DTR Output Operation status (UP
→
External)
DSR Input Operation status (External
→
UP)
Communication format
System Asynchronous system
Data length 8 bits
Stop bit 1 bit
Parity None
Baud rate 1200/2400/4800/9600 bps (Menu switching)
Set the transfer rate to 9600 when upgrading the firmware on the PRT-13 board.