Common Problems

This page covers common digitizer, system and application driver configuration problems which can cause the digitizing tablet, the Windows pointer, and digitizer-aware applications to work erratically or not at all. For a complete list of digitizers supported by manufacturer and model, and their configuration options, see DIGITIZE.TXT.

Digitizer Problems

As shipped and installed, the Virtual Tablet Interface drivers cause your digitizer to work like a large, absolute mouse on the Windows desktop. This means the four corners of the active area will map to the four corners of the Windows display. Positioning the puck or stylus in the center of the digitizer should place the Windows cursor in the middle of the desktop. If this default behavior is not the case, then the Virtual Tablet Interface drivers are not communicating with the digitizer correctly.

The Tablet Manager can be extremely helpful in diagnosing driver or digitizer configuration problems. For details on how to open, navigate and use the Tablet Manager, please refer to the Tablet Manager’s documentation.

Initial Steps to Perform

To diagnose a driver or digitizer configuration problem, perform these initial steps:

1 Close all Windows applications so that nothing except the Windows desktop (Explorer or Program Manager) is running. This means there are no icons in the task bar (Windows NT/9X) or the desktop (Windows 3.1).

2 Open the Tablet Manager by clicking on its icon in system tray next to your clock or by selecting it from Start\Programs\Virtual Tablet\Tablet Manager (Windows NT/9X) or clicking on its icon in the Virtual Tablet program group of the Program Manager (Windows 3.1).

3 Clear any custom features you may have enabled by clicking the Default button at the bottom of the Tablet Manager’s window and answer Yes when asked to apply defaults to all tabbed dialogs.

4 Switch to the Device Tab and check the device selected under Type to make sure you chose the correct device type during setup. If not correct, select the device connected to the computer from the list.

5 Once the device is correct, click the Reset Now button from the Reset section of the Device Tab.

6 Finally, switch to the Status Tab to begin diagnosing the problem by checking each of the values described in detail below.

Note: Some digitizers require movement of the puck a button transition in order to send data, which will be reported on the Tablet Manager’s Status Tab. If the values in the Driver section of the Status Tab do not change after several seconds, try moving the puck around the active area of the digitizer or pressing a button. You may also have to power your digitizer off-and-on.

Most of the issues described below pertain to the Driver section of the Status Tab (shown below) with Splits per Second checked. Please make sure this box is checked before proceeding and then examine each field in the Driver section as follows.

Port Interrupts Are Zero

Possible device driver conflict. Make sure you removed any other digitizer Windows drivers before, or immediately after, installing the Virtual Tablet Interface. If you need assistance, contact the digitizer manufacturer.

Possible interrupt conflict. Make sure you do not have an internal modem or other serial port device sharing the same interrupt as the digitizer serial port. Try removing the card and restart Windows. If you need assistance, contact the computer manufacturer.

Possible invalid COM port. Check the Port section of the System Tab and make sure the serial port is correct and the one to which the digitizer is connected.

Possible interrupts disabled. Switch to the Driver Tab and make sure interrupt processing is enabled.

Possible digitizer configuration. Make sure the digitizer is configured correctly and is transmitting packets continuously. Consult the file Digitize.txt in your Virtual Tablet directory for the correct configuration.

Possible hardware interface. If the digitizer has been moved from a UNIX or other non-PC machine, you may need to add a null modem cable (available at most computer stores) to the digitizer before connecting to the PC.

Port Errors Are High

Possible invalid digitizer type. Switch to the Device Tab and make sure the Type matches the digitizer connected to your computer.

Possible digitizer configuration. Refer to the file Digitize.txt in your Virtual Tablet directory and make sure the digitizer is configured correctly for the baud rate, data bits and stop bits. For some models, this may require changing dipswitches. If you need assistance, contact the digitizer manufacturer.

Packet Errors Are High

Possible invalid digitizer type. Switch to the Device Tab and make sure the Type matches the digitizer connected to your computer.

Possible digitizer output format. Refer to the file Digitize.txt on your registered disk or in the download directory and make sure the digitizer output is configured correctly. Review any Notes in the file for special configuration requirements. If you need assistance, contact the digitizer manufacturer

Packets Ignored Are High

Possible report rate. This is not a problem unless it occurs when moving the puck around the digitizer’s active area. However, you may wish to lower the report rate from the Device Tab as a performance measure.

Pointers Ignored Are High

Possible report rate. This is not a problem unless it occurs when moving the puck around the digitizer’s active area and a clipping area is not defined. However, you may wish to lower the report rate from the Device Tab as a performance measure.

Contention Active. If contention is enabled and you are using a mouse, then Contention Active will indicate "Yes" and digitizer pointer events will be ignored until you click a digitizer button. Otherwise, this field will say "No."

System Problems

These problems assume the digitizer is configured and working correctly at the Windows desktop. In other words, the four corners of the active area will map to the four corners of the Windows display and you are able to select icons, open applications, and generally use the digitizer like a large, absolute mouse.

Mouse Pointer Interference

Dueling cursors. If the digitizer is installed on a system with a relative device like a mouse, you may have to set positioning to Relative in order to avoid “dueling cursors” which makes using both devices at the same time difficult. Alternatively, simply remove the puck or stylus from the digitizer’s active area when not in use. Finally, you can also enable the Contention feature from the Driver Tab that is specifically designed to eliminate this problem allowing both devices to be used interchangeably.

Mouse Pointer Disabled

System Mouse Ignored. On some Windows 9X systems, the system mouse driver can become confused the first time after installing a new pointing device and forget its previous settings, including to load and use another Microsoft-type mouse connected to a serial or PS/2 port. If you have another mouse on the system that stops working after installing the Virtual Tablet Interface, simply add it back through the Control Panel/Add New Hardware. Also, make sure you installed the Virtual Tablet Interface with the “Use Microsoft-compatible Mouse” option enabled (which is the default).

Mouse Double-Clicks Erratic

Mouse Support in DOS

By default, under Windows 9X the Virtual Tablet Interface provides mouse support for full screen DOS applications. However, this may conflict with DOS applications that wish to use the serial port for direct digitizer input or other uses. To disable mouse support in full screen DOS windows under Windows 9X, uncheck the Enabled box under the Mouse section in the System Tab of the Tablet Manager.

PCI Serial Port Cards

PCI serial port cards often use non-standard base addresses and interrupts. For Windows 9X and Windows 3.1 only, you must add entries in the SYSTEM.INI file under the [386Enh] section describing these values as follows:

Where Com1Base, Com2Base, Com3Base and Com4Base equal hexadecimal values for the I/O base address of the port; and Com1Irq, Com2Irq, Com3Irq and Com4Irq equal the decimal value for the interrupt request line used by the port.

Application Problems

AutoCAD Configuration Error

Pointer Driver. Make sure AutoCAD is configured to use a Wintab compatible pointing device and not a specific digitizer-type model. As a rule, the "Accept Input from Mouse and Digitizer" option should be enabled. In rare cases, you may need to configure AutoCAD to use the “Current System Pointing Device”, exit AutoCAD, then restart AutoCAD and configure AutoCAD back to using a Wintab compatible pointing device in order to reset AutoCAD’s pointer registry values.

Screen Area Too Small

Possible clipping conflict. Wintab compatible applications may define their own screen pointing areas which conflict with the clipping area defined in the Manager if locked for the Default Tablet.

Clipping, Contention, Cropping and Positioning Ignored

ArcView Buttons Incorrect

The Virtual Tablet Interface is fully compatible with ArcView for Windows. Button assignments are fixed and pre-assigned to digitizer buttons as follows:

          Button 1 = left click                           (start digitizing line)
          Button 2 = left double-click             (finish digitizing line)
          Button 3 = middle double-click       (switch digitizing mode)
          Button 4 = right click                        (run popup menu choices)

While users may re-map other digitizer buttons to these values, only these four buttons will be interpreted correctly by ArcView for their required actions.

Visual Tablet (ZMC) Setup Tips

4 Select the 'System' tab and highlight 'Wintab Compatible Digitizer' on the menu labeled 'Current Pointing Device.

7 Check the Virtual Tablet Interface Tablet Manager. If it is not configured in Windows to use the entire tablet area, then reset the tablet pointing area in Windows to use the entire tablet.

10 Select the 'System' tab and highlight Visual Tablet on the menu labeled 'Current Pointing Device. You will be asked how many mouse buttons should be mapped to puck buttons. Answer: 2. Next, the correct button numbers are 1 and 2. Next you will be asked to pick two points to define your screen or Mole area. Use the screen targets on your template to select the AutoCAD screen area. If Visual Tablet fails to appear on the menu, select the 'FILES' tab. Then select 'Device Driver File Search Path'. Click on the 'Add' button and type in 'c:\vistab2000' (the default installation directory).

14 If the Visual Tablet icons are not properly calibrated and aligned to your tablet, do a POPCFG.