Two I/O Link Extender cards and their associated Fiber Optic Coupler modules are required at each end of the I/O link extension, one for Link A and one for Link B.

A Fiber Optic Coupler module provides attachment for one, two, or three fiber optic cables at the local card file. A second Fiber Optic Coupler module terminates a single optic cable at the remote IOP card file.

There can be a mix of Standard and Long Distance I/O Link Extenders in a subsystem; however, both ends of the 'A' and 'B' links must be the same type.