41CL User Manual
© 2019, Systemyde International Corporation
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11.
The 41CL circuit board contains a simple RS-232C serial port. The Receive Data,
Transmit Data and Ground signals for the serial port are present on the programming
connector for the CPLD on the board. The optional serial connector contains a plug
for this connector, connected through a cable to a 2.5mm stereo jack mounted in a
blank Port cover. The serial connector is designed to occupy Port 1 on the calculator
only. While it can be plugged into any other Port, doing so will interfere physically
with the remaining Ports because of the cable.
CAUTION!
The tension holding a 2.5mm plug in the serial connector jack is higher
than the tension holding the blank port cover in the calculator body. This means that
trying to pull out the plug will tend to pull the blank port cover out of the calculator,
potentially damaging the internal connections to the serial connector jack. So always
remember to hold the blank port cover in place when attempting to remove the serial
port plug from the calculator.