The vast majority of simple questions you have about your hardware can be answered by visiting the manufacturer’s Web site. You can also find out about hardware upgrades and options for the specific model of hardware you have, expansion capabilities, and more.
Many Web sites provide a visual schematic to show you how everything in your phone system connects together. If you are familiar with a manufacturer’s Web site, you can alert a carrier, who may be trying to troubleshoot the hardware but is unfamiliar with the setup.