The number of FTDI virtual COM ports that may be installed in a system can be limited by setting the MaxDevs parameter. MaxDevs defaults to 0, meaning that the feature is disabled and the driver will always attempt to create a COM port. The default can be overridden by including a non-zero MaxDevs value in the FTDIBUS.INF service key section.
[FtdiBus.NT.AddService]
AddReg = FtdiBus.NT.AddService.AddReg
[FtdiBus.NT.AddService.AddReg]
HKR,Parameters,"MaxDevs",0x00010001,3
In this example INF file fragment, the maximum number of devices is set to 3.
This value is held in the registry key located at
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\FTDIBUS\Parameters\MaxDevs
If an attempt is made to install more than MaxDevs devices, a Code 10 error ("This device cannot start") is generated for the new device.
Note that setting MaxDevs to a value other than zero will radically alter the behaviour of the driver; please contact FTDI if you think you have to change MaxDevs.
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Limiting the Number of COM Ports That Can Be Installed
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