SerialKeys Advanced Usage and Troubleshooting

This article describes common troubleshooting tips for SerialKeys and how to use more sophisticated methods of access. SerialKeys enables you to control the computer by using an alternate input devices.

For additional information about setting up SerialKeys or programming an assistive aid, click the article number below to view the article in the Microsoft Knowledge Base:

SerialKeys is usually used by accessibility aids to provide input in place of that provided by the computer's keyboard or mouse. The Microsoft implementation of SerialKeys follows the connection and communication protocol outlined in the General Input Device Emulating Interface (GIDEI) protocol defined by the Trace Research and Development Center at the University of Wisconsin. Details of the GIDEI protocol are available from Trace at the following Trace Research and Development Center Web site: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

Troubleshooting SerialKeys

If you are using SerialKeys and the aid stops sending keys successfully, try the following items:

• Check to make sure you included any necessary periods in your key names.
• Send three null characters. (The null character is different from a zero; usually you can generate it on the aid by pressing CTRL+@.
• Reset both the aid and SerialKeys to 300 baud. (If there is a communication difficulty, SerialKeys may automatically reset itself to 300 baud, making it unable to communicate with the aid if the aid is sending at a different rate.)

Note the following items:

• SerialKeys uses hardware handshaking (DTR/RTS) and software (XON/OFF) handshaking to control the flow of characters from the aid. Characters may be lost if the aid ignores these handshaking signals.
• Microsoft Windows NT 4.0 manages the COM ports, including the hardware interrupt lines. Windows NT does not allow another device to use or share the interrupt line that SerialKeys is using. This means that if, for example, you have SerialKeys turned on using COM port 1, you cannot use the Windows Terminal program on COM port 1. Also, if you have SerialKeys on COM 1, and another program is experiencing problems while using COM 3, you must move the program or SerialKeys to COM 2 or COM 4. See your computer documentation for details on how COM 1 and 3 and COM 2 and 4 should be set, and whether the computer supports COM ports 3 and 4.

Microsoft recommends programming the aid to use the IBM Enhanced Keyboard (101 keys). Even if the computer does not have this keyboard, SerialKeys functions as the 101-key keyboard. This can be to your advantage, because some programs recognize the additional keys, enabling you to use additional features. If you choose to program the 83-key or 84-key keyboard, there are a few exceptions you should be aware of:

• To use the Break function, you would ordinarily press and hold down the CTRL key and press the SCROLL key. For SerialKeys, press and hold down the CTRL key and press the PAUSE key.
• To use the Pause function, you would ordinarily press and hold down the CTRL key and press the NUM LOCK key. For SerialKeys, just press the PAUSE key.

Advanced Mouse Movements

It is a good idea to program at least a square or selection on the aid to move the mouse in the four directions by 1, 10, and 100 units. This lets you make small, fine movements and large, fast movements. For example:

Resetting SerialKeys

If you are using SerialKeys in a multiple-user environment, the first command you send to SerialKeys should be the reset command. This ensures that SerialKeys operates at 300 baud and is ready to accept your keyboard and mouse actions. The reset command consists of sending three null (ASCII 0) characters with the aid configured to 300 baud. You can usually generate a null character on the aid by pressing CTRL+@.

Using Lock and Release

You can use this command to hold a key down and lift it back up again as separate actions. Its primary use is in using SerialKeys in combination with MouseKeys.

1. Turn on MouseKeys by pressing left ALT+left SHIFT+NUM LOCK.
2. Decide which direction you want to move the mouse. Find out which numeric keypad key moves the mouse in that direction in MouseKeys.
3. Send a lock command with that key name. For example, to move the mouse pointer to the right:

   [esc],lock,kpright.
   					

4. When the mouse pointer has moved as far as you want in that direction, send the release command:

   [esc],rel.
   					

You can program the lock part and the release part of this sequence under a different selection on the aid so that you do not have to type them each time you use them. Make sure to include the commas and periods.

NOTE: MouseKeys also enables you to hold down and release a mouse button or click a mouse button.

Using the Keyboard Combine Command

If you want to program a modifier key and another key under a single selection on the aid, use the combine command to place several keystrokes under one selection on the aid. This can be useful for common multiple-key command combinations that are required by software. There must be commas between the keys and a period at the end. No more than five keys can be combined. For example:

Using the Mouse Goto Command

This moves the mouse to a specified location. You should send the moureset command first. Both the horizontal and vertical direction numbers require only a plus (+) sign. (See the example for moving the mouse earlier in the "Advanced Mouse Movements" section.) For example:

Using the Mouse Anchor Command

You can use this command to anchor the mouse pointer to a position within a Windows-based program. If you change the active window between setting the mouse anchor and returning to that anchor, the mouse anchor command does not work. The following example shows how to use the mouanchor (mouse anchor) command to mark a current window position, go to a new location and click the mouse to select a new tool, go to another new location and click the mouse to select another color, and then return to the location you left to use that tool:

Using the Baudrate Command

This command enables you to change the SerialKeys baud rate from the aid. The possible baud rates are 300; 600; 1,200; 2,400; 4,800; and 9,600. This command is never absolutely necessary because you can also set the baud rate in SerialKeys. For example: If you decide to run SerialKeys at a baud rate faster than 300, be aware of the special automatic reset feature in SerialKeys. When SerialKeys receives three consecutive characters with a transmission error, it automatically resets to 300 baud. This enables people in a multiple-user environment to place SerialKeys in a known state (300 baud). SerialKeys signals any transmission problem with a short beep. If SerialKeys resets to 300 baud, it generates a long beep. SerialKeys also signals a baud rate change with a long beep.

The information in this article is excerpted from the Customizing Windows for Individuals with Disabilities series of documents. For additional information about customizing different versions of Windows for people with disabilities, click the article number below to view the article in the Microsoft Knowledge Base: