Dell Latitude D631 (Early 2009) - Manual (Page 23)

About Your Computer 23
M O D E M C O N N E CT O R (RJ-11)
USB C O N N E C T O RS (2)
SE R I A L C O N N E CT O R
VI DE O C O N N E C T O R
AC A D A P T E R C O N N E CT O R
Connect the telephone line to the modem connector.
For information on using the modem, see the online modem
documentation supplied with your computer (see "Finding
Information" on page 11).
Connects USB devices, such as a mouse, keyboard, or
printer.
Connects serial devices, such as a mouse or handheld device.
Connects video devices, such as a monitor.
Connects an AC adapter to the computer.