Samsung LS19TRTLB-XAA - Manual (Page 15)

Earphone jack [ ] Headphone connection terminal.
The Microphone
connection terminal (MIC) Connect a microphone to the MIC terminal.
USB
(USB Connection
Terminal)
Connect USB devices such as a mouse, keyboard and external storage
devices (DSC, MP3, external storage, etc.).
LAN
(LAN Connection
Terminal) Connect when using it as a monitor.
AUDIO IN Connect the audio cable for your monitor to the audio port on the back of
your computer.
See Connecting Cables for further information regarding cable connections.