Armored Fiber Optic Cable Structure and Types

August 14, 2021

Armored Fiber Cable Structure

Armored fiber cable has important applications in long-distance optical telecom lines, primary and secondary trunk line transmission.

The armored fiber optic cable is to wrap a layer of protective “armor” on the outside of the optical fiber, which is mainly used to meet the requirements of anti-rodent and moisture resistance.

Generally, the armored fiber patch cable has a metal armor inside the cable outer sheath to protect the inner optical fiber. This armor layer has the function of strong pressure and stretching resistance, and can prevent rodents and insects.

Armored Fiber Cable Type

According to where the armored fiber cable is installed and used, we can simpliy separate it as 2 main types, the indoor and outdoor armored fiber optic cable.

Indoor Armored Fiber Cable

The armored fiber cable that network management usually comes into contact with is mostly used for connecting two optical fiber network devices used in the computer service room. Such armored fiber is relatively short in length, and usually called armored fiber patch cable or armored fiber patch cord.

The structure of a single-core indoor armored optical cable is:

  1. Tight buffer optical fiber
  2. Aramid yarn (resistance of tension)
  3. Stainless steel hose (resistance of compression, bending, and rat bite resistance)
  4. Stainless steel braided wire (resistance of torsion)
  5. Outer sheath (PVC usually, there are also flame retardant PVC, LSZH, Teflon, silicone tube, etc. according to different functions)

There are single armor and double armor for indoor armored fiber cable. Single armor refers to an armored fiber cable that does not contain stainless steel braided wires. While double armor refers to an armored fiber cable containing stainless steel hose and stainless steel braided wire.

Outdoor Armored Fiber Cable

There are light armor and heavy armor for outdoor fiber optic cable. Light armor has steel and aluminum tape, which are used to strengthen and prevent rodents from biting.

And heavy armor is a circle of steel wire on the outside, which is generally used for riverbeds and seabeds. This heavy armored fiber optic cable is also known as SWA (steel wire armor) cable.

  1. Optical fiber
  2. Uni-tube or stranded loose tube
  3. Central strength member
  4. Steel / Aluminum tape
  5. Water blocking materials
  6. Outer cable sheath

In general, armored fiber optic cables are more expensive than non-armored fiber cables. And steel tape and aluminum tape are much cheaper than aramid yarn.

Advantages and Disadvantages

Advantages: High tensile, High compression, Anti-rodent; Resistance to improper torsion and bending damage, Simple construction, Saving maintenance costs, Adapt to various harsh environments and man-made damage.

Disadvantages: The weight is heavier than ordinary fiber optic cables., and price is also higher.


The armor laying provides the indoor or outdoor armored fiber cable necessary protection on tension, crush and other mechanical performance. As a result, the armored fiber cable can be a reliable link in all kinds of optical communication networks.

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Tony Lau is technical manager and co-founder at HOC. He loves writing about content optical fiber communications, specializes in fiber optic cables, FTTH turnkey solutions, ADSS cable, and ODN networks.

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