Cisco GS7000 Installation And Operation Manual page 149

The reversible pin adaptor is color coded. One side is blue and the other side is red.
To install the module in a transmitter slot, assemble the pin adaptor on the module
with the red side facing outward. To install the module in a receiver slot, assemble
the pin adaptor on the module with the blue side facing outward.
The following illustrations show how to assemble the pin adaptor to the module.
CAUTION:
To prevent electrostatic damage to electronic equipment, take ESD
precautions, including the use of an ESD wrist strap.
Removing and Replacing Modules
129