R&M Data Center Handbook

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Adapters
There are two types of MPO adapters based on the placement of the key:
Adapters key-up to key-down (left), key-up to key-up (right)
• Type A: Key-up to key-down
Here the key is up on one side and down on the other.
The two connectors are connected turned 180° in
relation to each other.
• Type B: Key-up to key-up
Both keys are up. The two connectors are connected
while in the same position in relation to each other.
Connection rules
1. When creating an MPO connection, always use one male connector and one female connector plus
one MPO adapter.
2. Never connect a male to a male or a female to a female.
With a female-to-female connection, the fiber cores of the two connectors will not be at the exact same height
because the guide pins are missing. That will lead to losses in performance.
A male-to-male connection has even more disastrous results. There the guide pins hit against guide pins so
no contact is established. This can also damage the connectors.
3. Never dismantle an MPO connector.
The pins are difficult to detach from an MPO connector and the fibers might break in the process. In addition,
the warranty becomes null and void if you open the connector housing!
Cables
MPO cables are delivered already terminated. This approach requires greater care in planning in advance but has
a number of advantages: shorter installation times, tested and guaranteed quality and greater reliability.
Trunk cables/patch cables
Trunk cables serve as a permanent link connecting the MPO modules to each other. Trunk cables are available
with 12, 24, 48 and 72 fibers. Their ends are terminated with the customer's choice of 12-fiber or 24-fiber MPO
connectors. MPO patch cords will not be used until 40/100G active devices are employed (with MPO interface).
The ends of MPO patch cords are terminated with the customer's choice of 12-fiber or 24-fiber MPO connectors.
Trunk/patch cables are available in a male – male version (left) and a female – female version (right)
Harness cables
Harness cables provide a transition from multi-fiber cables to individual fibers or duplex connectors. The 12-fiber
harness cables available from R&M are terminated with male or female connectors on the MPO side; the whips
are available with LC or SC connectors.
Y cables
Y cables are generally used in the 2-to-1 version. A typical application is to join two 12-fiber trunk cables to a 24-
fiber patch cord as part of a migration to 100 GbE. The rather rare version of 1 to 3 allows three eight-fiber MTP
connectors to be joined to a 24-fiber permanent link, e.g. for migration to 40GbE.
Page 130 of 156 © 08/2011 Reichle & De-Massari AG R&M Data Center Handbook V2.0