Cannot connect to the pad on Windows 7

There is a port access issue on Windows 7 where Office 2013 is in use.

When Office 2013 or Lync run there is some start-up code that opens the STU pad. Afterwards the pad is held open and is not available for exclusive access.

The Signature and STU SDKs normally require exclusive access to the signature pad to prevent potential conflicts caused by different applications trying to access the pad simultaneously.

See this related FAQ for more information: STU HID Diagnostic Tool

The access issue does not happen with Office 2013 on Windows 8.

In addition it does not occur with the STU-430 or 530 because their firmware defines a different type of USB interface.

The solutions are different depending on the SDK in use:

STU SDK

The workaround is for the application to use shared rather than exclusive access to the STU pad:
e.g. change  

 var r1 = tablet.usbConnect(usbDevices_arr[usbDevices_index], true);

to

 var r1 = tablet.usbConnect(usbDevices_arr[usbDevices_index], false);

STU SigCaptX

With the STU SDK cross-browser the following syntax is required to enable a shared connection:

 return intf.connect(m_usbDevices[0], true);

Signature SDK

To fix the shared access issue using the Signature SDK it is necessary to create a registry value as described below.

32-bit SDK: [HKEY_LOCAL_MACHINE\SOFTWARE\Florentis\sd]

      "stuShared"=dword:00000001

64-bit SDK: [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Florentis\sd]

     "stuShared"=dword:00000001

A danger with using shared access is that another application could also open the same STU device and then I/O commands could conflict with each other.
Steps should be taken to avoid this if at all possible.