6  IBM LTO Ultrium tape drives or 3592 tape drives
Mounted in the TS3500 Tape Library, one or more units that read and write data that 
is stored on tape cartridges. IBM LTO Ultrium tape drives and 3592 tape drives may 
not be mixed in the same frame. IBM Ultrium tape drives use LTO Ultrium tape 
cartridges; 3592 tape drives use IBM® TotalStorage® 3592 Enterprise Tape 
Cartridges.
 7  Front door
The front door of any frame. When you order the Capacity Expansion Feature for the 
Model L22, L32, or L52, the storage slots inside the front door become enabled and 
can increase the tape library's capacity.
 8  Door safety switch
A device in each frame that shuts down the motion power to the cartridge accessor 
whenever the front door is opened.
 9  I/O stations
Up to two cartridge compartments on the front door of base frames of the TS3500 
Tape Library that allow you to insert or remove tape cartridges without the library 
performing a reinventory of the frame. 
 10  Operator panel and operator panel controller
Located on the front of the base frame, the operator panel is the set of indicators 
and controls that lets you perform operations and determine the status of the library. 
The panel consists of the library power switch, a power-on indicator, a touchscreen 
liquid crystal display (LCD), and the controller for the I/O stations. The operator 
panel controller is a circuit board that facilitates communication between the 
operator panel and the accessor controller.
 11  Enhanced frame control assembly
An assembly of components that facilitate RS-422 communication between the drives 
in a frame and the accessor controller and operator panel controller. Only Models 
L23, D23, L53, and D53 are equipped with the enhanced frame control assembly, 
which includes two power supplies, both of which can provide power to the library 
and all drives in a frame.
 12  Patch panel 
A panel that houses the cable connections for the drives that use Fibre Channel 
interfaces. If frame is equipped with the TS7700 backend switches (not shown), the 
patch panel is removed.