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I get the following error message when I try to link my Spirometer to the PC? "Spirometer not responding. Please check the unit is connected and is ready for PC communications"

Problem

On some computers, the serial link used to communicate with the Spirometer can be unreliable, leading to error messages such as ‘Spirometer not responding’

Example

Cause

Many modern computers use a 16550 UART chip for managing the COM port. This has an internal buffer (known as a FIFO) which improves the performance of the port when used with high-speed modems, but can sometimes cause connection problems.

Solution

The FIFO can be disabled on the COM port used to connect to the Spirometer, giving improved reliability. The procedure for doing this depends on the Windows version as follows:

Windows 3.1, Windows 3.11, Windows NT 3.5

  • Using Notepad, edit the file SYSTEM.INI in the Windows directory
  • Look for the section headed [386Enh]
  • Add the following line anywhere within the section: COM1FIFO=0 (if you are using COM1)
  • If you are using a different COM port for spirometry, adjust the above line accordingly
  • Save the file and restart Windows

Windows 95, Windows 98, Windows ME, Windows NT 4

  • Click the Start button.
  • Select Settings, then Control Panel
  • Double-click the System icon
  • Select the tab marked Device Manager
  • Select Ports (COM & LPT)
  • Double-click the COM port you use for spirometry
  • Select the tab marked Port Settings
  • Click the Advanced. button
  • If the box marked 'Use FIFO buffers' you can low the buffer rates down or clear it
  • Click OK to close all dialog boxes

Windows 2000/XP

Press the Start button Go to Setting, a new menu will pop out to the left. Click on Control Panel. When the control panel comes up find the icon that says System and double click it.

  • The system properties box will come up, click on the Hardware tab
  • You will see a button labelled Device Manager
  • Click on this button and it will open the device manager
  • Select Ports (COM & LPT)
  • Double-click the COM port you use for spirometry
  • Select the tab marked Port Settings
  • Click the Advanced. button
  • If the box marked 'Use FIFO buffers' you can low the buffer rates down or clear it

Windows XP


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