Windows - Advanced Navigation Certus OEM Reference Manual

Certus Reference Manual • Configuring and Monitoring Certus

8.2.4.1 Windows

There is a well known problem with USB serial devices under Windows known as "crazy mouse". The problem
occurs when the system mistakenly installs the USB serial device as a mouse. If you experience this problem,
often a restart will resolve it. Otherwise there is a tool that can fix this issue available at
http://www.stentec.com/anonftp/pub/wingps/pnpblockersetup.exe.
If the serial port does not show up when you plug in the FTDI USB to RS232/RS422 adaptor cable, you may
need to install the drivers from www.ftdichip.com/Drivers/VCP.htm.
When operating Certus on Windows at a high data rate, data can be lost due to the latency of the FTDI driver.
To resolve this problem the latency of the driver should be reduced to 1 ms:
1. Start the Windows Device Manager (1) and find the Ports section (2).
2. Identify the specific COM port being used (3) by dis-connecting and re-connecting the USB to RS232 /
RS422 adaptor cable.
3. Right click on the identified COM port and select Properties. Select the Port Settings tab (4) and select
Advanced (5).
4. Change the Latency Timer value (6) to 1 msec then press OK (7), and OK again for the previous window.
Figure 57: Setting the Windows Port Latency Value - 1
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