Dell Dimension 4400 - Manual (Page 58)

Windows Label
This Microsoft® Windows label provides the product key for your copy of Windows. You will need this information if you ever reinstall Windows.
USB Connectors
For quick connections, Dell recommends using the front USB connectors for USB devices such as digital cameras, gaming controllers, and scanners. Use the
back-panel USB connectors for USB devices that are seldom disconnected, such as USB mouse and keyboard devices.
Headphone Connector
Use the headphone connector to attach headphones and most speakers for listening to all sounds in your computer, including your CD player and system
sounds such as beeps.
Service Tag
This label lists your computer's service tag and your Express Service Code (if applicable). If you call Dell technical support, use your Express Service Code to
route the call directly to the correct support personnel. The Dell technical support staff will ask for your service tag.
Back View
Power Connector
NOTICE: This system supports the use of a USB hub. However, do not connect two or more USB hubs to a USB connector. Doing so may cause the
system to unexpectedly reboot.
HINT: If you attach a USB device that was not included in your original computer order, you may need to install a specific driver to make the device
work. Check the documentation that came with the device or contact the USB device manufacturer for more information.
HINT: Express Service may not be available in some countries.