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MTP/MPO Cables Polarity

MTP/MPO Cables Polarity

In any installation, it is essential to ensure that an optical transmitter at one end is connected to an optical receiver. This matching of the transmit signal (Tx) to the receiving equipment (Rx) at both ends of the optical fiber link is referred to as polarity.
In standard cabling systems, this connection is ensured by single fiber connectors (usually SC or LC). On the other hand using 12 to 96 fibers MTP/MPO connectors in high-density cases is a better solution.
The Key, at the ends of connectors, allows recognizing fibers position. The orientation of Key ensures a right link.

key up key down

 

 

There are three different MTP/MPO trunk cable types:

metodo A

Method A (Straight):

Key Up – Key Down

The connector A’s Key will be placed upward, whereas at the other end the connector will be upside down. This method ensures the same fibers positioning on both cable sides (ex.: the fiber in the 1st position of the connector A matches with the fiber in the 1st position of the connector B).

 

 

metodo B

Method B (Reversed):

Key Up – Key Up,

Key Down – Key Down

This type has both connectors in the same position (Key Up/Key Up, Key Down/Key Down), achieving reversed fibers position from side to side (ex.: the fiber in the 1st position of the connector A matches with the fiber in the 12th position of the connector B).

 

metodo C

Method C (Flipped by Pairs):

Key Up – Key Down

As well as method A for the Key, optical fibers within the cable are flipped by pairs (ex.: the fiber in the 1st position of the connector A matches with the fiber in the 2nd position of the connector B).