Compaq TFT8030 User Manual page 12

If only one of the user input channels has valid video connected,
that input channel is the default at power-up. If the user input
video is in sleep mode, the monitor displays the "Going to
Sleep" OSD message and enters sleep mode.
Input channels that do not have a user-selected input follow the
input recall detection scheme described in the previous section
and are available for display by selecting the Input Channel
button.
If the selected user input does not have valid video signals
present, the monitor returns to the Input Recall detection mode
described in the previous section. If no valid signals are detected
on either input channel, the monitor displays the "Check Video
Cable" OSD message and enters sleep mode.
If both Channel 1 and Channel 2 inputs have been set using the
OSD, the Default Input Channel set by the user with the Input
Select function in the OSD has priority at all times that valid
video is present. If the default input video is in sleep mode, the
monitor displays the "Going to Sleep" OSD message and enters
sleep mode. If the default input has invalid video (i.e., the host
PC is off or video cables are not attached), the monitor switches
to the other input channel if valid video is present. However,
once valid video is restored to the default input, the monitor
detects and displays that input automatically. If the two selected
inputs are in sleep mode, or if there is no physical connection,
the monitor displays the appropriate OSD message and enters
sleep mode.
10 TFT8030 User's Guide