The outermost layer of the cable, which carries the print legend with fiber type, count and footage marks. Outdoor cable uses black polyethylene for UV and water resistance; indoor cable uses PVC or low-smoke zero-halogen compounds rated OFNR for risers or OFNP for plenums. Jacket color on premises cable flags the fiber type: yellow singlemode, orange OM1 or OM2, aqua OM3 or OM4, lime OM5.
Read me the footage off the jacket at both ends so we've got a length for the as-builts.
Also heard as
- sheath
- outer jacket
Related terms
Buffer
The protective plastic layer or tube around coated fiber, either a tight 900 µm jacket or a loose gel-filled tube.
Aramid yarn
The yellow strength yarn inside fiber cables that takes the pulling load so the glass does not.
Fiber color code
The fixed sequence of twelve colors that identifies each fiber and buffer tube in a cable.
OM grades
The OM1 to OM5 performance classes for multimode fiber, each rated for bandwidth and reach at a given data rate.