Sony PCG-XG29 - Manual (Page 80)

VAIO® Notebook User Guide $&
To connect both a mouse and keyboard at the same time, use the optional
PS/2 division connector. If the wheel function of the PS/2 mouse does
not operate, connect the mouse to the serial port using the PS/2 serial
adapter that is supplied with your mouse. You can also use one of both of
the USB ports to connect a mouse and keyboard at the same time.
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See “Using the Keyboard” on page 23 for more information on using the keyboard.
See the manual that came with your mouse or keyboard for more information on installation
and use.
Before you connect or disconnect the PS/2 mouse or keyboard, turn off the computer.
Do not connect or disconnect the PS/2 device (keyboard or mouse) when the computer is on
as this may cause malfunction.
A Sony USB mouse PCGA-UMS1 (optional) is a USB device. You must connect it to the USB
connector.