User`s manual

Step-7 : Install Faceplate Panels
The Agilent E1401 and Agilent E1421 mainframes are shipped from the
factory with faceplate panels installed to cover the module slots. To avoid
electrical shock, always cover unused slots with the faceplate panels.
Figure 4-7. Installing Faceplate Panels
4-16 Configure and Install Instruments C-Size Configuration Guide