Base-2 LC-LC patching modules
Users building a Base-2 LC link may choose to connect LC trunk harnesses at the rear of the module with LC patchcords at the front. This is common with serial links where equipment ports on the server and switch are both of a LC duplex type. The most common fiber count would be 12 fiber so as to maximize the density of the module (6 x LC duplex ports).
Base-8, 12 and 24 MPO-MPO patching modules
MPO patching modules can be used in greenfield data centers to connect MPO backbone trunk cables at the rear of the module, to MPO patchcords at the front of the module. This connection method is common when the transceivers on the server or switch are parallel MPO type (such as QSFP for 40G). Alternatively, MPO patching modules can be used to connect MPO-LC equipment harnesses at the front of the module. This is an effective way of connecting to high-density switches where space is of a premium.