When troubleshooting input devices, always start with the simple solutions. Check to make sure the device is properly connected. Verify the cable is in good working condition and is not frayed. As with any hardware problem, start from the outside of the box.

After checking the physical connections of the input device, try rebooting the computer. Sometimes, an input device will be disconnected while in operation and a reboot is required. Pay attention to any errors that display during startup. The errors will be indicated either as a text error on the video display or a POST beep code. For example, if a keyboard is not properly connected, the user might get a beep code or a "301 error message".

Two common errors with input devices are incorrect character input and unrecognized devices. Both of these errors can result from a bad or outdated driver. Always check the manufacturer website for updated device drivers. Input devices will need the right driver to work correctly.

Keyboards
Keyboards are heavily used input devices. Due to the heavy workload and numerous movable components, keyboard failures are frequent. The best protection against keyboard errors is proactive maintenance. Figure lists some of the most common errors associated with the keyboard.

Mouse
The mouse is also a heavily used input device. Mice are prone to bad performance mainly because of dust and dirt corroding the components. Maintain a clean environment and clean the mouse frequently for optimal performance. Figure lists some of the most common mouse errors.

Scanners
Most scanner errors are either a direct result of a bad software install or an improperly connected device. Figure lists the most common errors associated with scanners.

Parallel Ports
Parallel ports will rarely fail. However, a more common problem is slow performance from a parallel device. The most common errors associated with parallel ports are listed in Figure .

USB Ports
Most new computers will be equipped with a Universal Serial Bus (USB) port. Today, USB ports are replacing the older serial port found on most computers. USB devices are based upon Plug and Play (PnP) technology. This means that USB devices should install and operate with minimal configuration. However, this does not mean that USB devices are free from errors. There are several common failures that are associated with USB devices:

• Missing or outdated driver
• Wrong cabling
• Defective hardware
• Resource conflicts

USB devices should load automatically in most versions of Windows. Windows 95 ORS2, Windows 98, Windows ME, Windows 2000, and Windows XP support USB. However, Windows NT does not support the USB standard. Sometimes while installing a USB device, Windows might prompt the user for the location of a USB device driver. In such cases, the technician will be required to find a suitable USB device driver. Most of the time, USB devices will be packaged with a disk that contains the device driver or users can visit the manufacturer website for the latest driver.

USB devices connect via USB cables. The USB device and cable must be the same speed to function properly. USB cables come in two speeds, low and high. If a faster device is connected to a slower cable, the signal can become corrupted over long distances. If a cable problem is suspected, replace the cable with a faster cable. Additionally, USB devices require an IRQ channel to work properly. The easiest way to check if there is a resource conflict is to check the Device Manager. To access the Device Manager in Windows, right-click on My Computer, select Properties, then the Hardware tab. Click the Device Manager button. The Device Manger will open, displaying the computer hardware devices. The Device Manager will indicate any device conflicts with an exclamation mark highlighted in a yellow circle. If this problem exists, it is necessary to verify that the device is properly installed and that the system resources have been allocated correctly.

Figure is a drag-and-drop activity on identifying input devices.
 

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