Cisco 2611 - Router - EN User Manual page 70

Replacing the System-Code SIMM
Figure B-5 Removing and Replacing the System-Code SIMM
Step 8
Caution
mounted on the rear side; therefore, when inserting the SIMM, always use the polarization
notch as a reference and not the position of the components on the SIMM.
B-10 Cisco 2600 Series Hardware Installation Guide
Position the new SIMM so that the polarization notch is located at the left end
of the SIMM socket.
To prevent damage, note that some Flash memory SIMMs have the components