Sony PCG-XG18 Primary User Manual page 69

You can use audio/video devices by connecting the AV devices to the
Mini Docking Station. See also the manuals and online help that came
with your AV devices.
If you connect the Mini Docking Station and an MD deck or a CD player
which has a CONTROL A1 or CONTROL A1 connector, you can play a
CD disc, create your own CD database, or edit an MD disc.
To use the CONTROL A1 connector on the Mini Docking Station,
switch the SERIAL/CONTROL A1 switch to CONTROL A1 .