Sony PCG-R505TSK - Manual (Page 63)

Connecting Peripheral Devices
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2 Remove the notebook from the docking station, while moving the computer
slightly back to disengage it from the two front latches of the docking
station.
Disconnecting the Docking Station when the Notebook is On
You can use the Start Menu in the Windows task tray or the UNDOCK switch on
the docking station to disconnect your notebook from the docking station while
the notebook is on.
Releasing the Notebook from the Docking Station
Removing the Notebook from the Docking Station
Pull release levers on either side of
rear corners of docking station