要看說明，因為外接盒的廠商很多
有一些要把Jumper用成ma，有一些要用成sl
要注意這一點，而且要注意外接盒最大能支援多大的硬碟
ub300不是2.5"的嗎
外接盒資訊如下
http://www.itsupplier.net/ITL-CB300U.htm
Host Interface
USB2.0 and USB2.0+IEEE1394
Data Transfer Rate
USB 2.0 : 480 Mbps,
IEEE1394: 400 Mbps,
Application
3.5" IDE Devices
Internal / External
External
Dimensions
206 (L) x 123 (W) x 33(H) mm
PCB Dimensions
70 (L) x 23 (W)x 1.5 (T) mm
Housing
Aluminum & Plastic
Color
Per customer request
Power Requirements
DC +12V
MTBF
30,000 POH or more
Vicat Softening Temp.
96℃(240℉)
Heat Distortion Temp
88℃(190℉)
Accessories
Color box full packing,
USB 2.0 A-B 80cm cable x 1,
IEEE1394 S-S 80cm cable x 1,
8cm CD driver disk x 1,
DC +12V Power adapter x 1,
Mounting screws parts bag x 1
Weight Per Piece
1500g
Spec. of Adapter
Input Range: AC110 V - 240 V
Output Range: DC+ 12 V
Output Current: 3 A
Safety: UL. CUL.TUV.PSE.
Capacity: 36 Watts
Export Packing
Piece Per Carton: 10 Pieces
Net Weight: 18 kg
Gross Weight: 16 kg
Meas: 1.8 CUFT
是這台嗎?如果不是請發問者貼上外接盒的產品資訊