Samsung PL64E8000GFXZP - Manual (Page 451)

ΠIf more than 2 PTP devices are
connected, you can only use one at
a time.
ΠIf more than two MSC devices are
connected, some of them may not
be recognized. A USB device that
requires high power (more than
500mA or 5V) may not be supported.
ΠIf the TV has no input during the
time set in Auto Protection Time, the
Screensaver will run.