Revision: A1.
3
The design and specifications are subject to change without notice for improvement
www.CommFront.com
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CONNECTIONS
(FIGURE 1: USB-TTL 3.3V CONVERTER CONNECTION DIAGRAM)
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TTL SIGNAL LEVELS
TTL Input
TTL Output
High (>2.0V)
High (3.3V)
Low (<0.8V)
Low (0.0V)
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TROUBLESHOOTING
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Make sure that the USB-TTL3.3V converter is connected to your USB port, and the driver is
installed correctly (as shown below); otherwise, please reinstall the driver (refer to
https://www.commfront.com/pages/usb-driver-installation-guide
for details).
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Perform a loopback test by using CommFront’s 232Analyzer software: Connect a USB-TTL3.3V
converter to your USB port, short pin
TX (TTL Out) to RX (TTL In) on the termination board,
and then send commands from the 232Analyzer software. You should receive an echo
of the commands sent. By performing a simple loopback test like this, you can test
both the transmitter and receiver of the USB-TTL3.3V converter. This is very helpful
when you are in doubt about the performance of your converter.