A collapsible bed frame includes a first cross unit including a first link member pivotally coupled to a second link member at a first pivot point, and a support unit operatively coupled to the first cross unit. The plural host devices respectively have a unique back-off value, and the plural peripheral devices respectively have a unique back-off value. A volume control may be provided with a mechanism for showing the non-mute volume control level of a volume when the volume control is muted.