User’s Manual10The unit utilizes heat-conducting techniques to transfer internal heat to thecase, especially to the bottom side of the unit.NOTE: Be sure not to remove the rubber feet, and always leavea space for air ventilation on the unit’s bottom side.2.2 Selecting Video FormatThe X4/X8/X16 DVR is designed to operate under either NTSC or PAL videoformats. The switch is positioned on the rear panel.2.3 Connecting Devices to the UnitThis section lists some important notices that should be read beforemaking any connections to the X4/X8/X16 DVR.NOTE: Connect short-term devices, such as USB ThumbDrive ®,USB CD-ROM, USB Hard Disk Drive, etc., only after the unit issuccessfully powered up.Connecting Required DevicesBefore power up the unit, you should connect cameras and a main monitor tothe unit for basic operation. If needed, connect a call monitor for displayingfull screen video of all installed cameras in sequence.Connecting Short-term DeviceIf you plan to install any short-term devices to the X4/X8/X16 DVR and usethem as part of the unit system, such as USB CD-ROM, USB Hard Disk Drive,etc, make sure those devices are connected only after the unit ispowered up. Because X4/X8/X16 DVR can recognize the external devicesonly after the power-up process is done completely.