Comparing the Different Types of Fiber Optic Drop Cable

Fiber optic drop cable is intended to complete the last-mile segment of a fiber network. Given the variety of environments and conditions fiber optic cable may encounter, choosing the appropriate type is vital for ensuring optimal performance and reliability in broadband networks. In this article, we will compare the different types of drop cables, focusing on their unique features and applications.

Every installation, whether it’s Outside Plant (OSP) or Fiber-to-the-Home (FTTH), has its own requirements for an optimal connection. Certain cables are designed specifically for burial applications, while others are intended for aerial installation. Rugged tight buffered cable is a better choice for situations where the drop cable may endure crushing, torsion, or extreme outdoor conditions. In contrast, loose-tube fiber cable is more flexible and often faster to install.

Flat Drop Cable: Flat drop cables are a flexible, versatile type of drop cable that is easily field terminated and used for many different applications. This fiber cable is usually sheathed in a polyethylene jacket, which gives it superior crush resistance. Flat fiber optic drop cable is available in both toneable and nontoneable varieties.

Round Drop Cable: Round fiber optic drop cable contains a single, bend-insensitive optical fiber. This optical fiber is surrounded by an aramid yarn strength element and a durable outer jacket. This type of drop cable is most often seen in a FTTH installation, connecting the NID box to the ONT.

Toneable Fiber Optic Drop Cable: Toneable drop cable contains a steel or copper wire contained within the jacket. This is ideal for burial installations, where the cable can then be traced and “toned” to using a tone generator instrument. A tone generator sends an electrical signal at a specific frequency through the metal wire embedded in the cable jacket. A technician can then use a probe to listen for the signal, allowing for quick location of a buried fiber cable.

Nontoneable Fiber Optic Drop Cable: For aerial installations, it isn’t necessary to utilize a toneable cable. A nontoneable cable does not contain a metal tracing element, since the drop cable can be visually identified. This can help lower overall material costs for the installation.

All Dielectric Self Supporting (ADSS) Cable: An ADSS cable can support its own weight over long spans without the need for a messenger wire. This reduces installation time, maintenance costs, and material costs.

Figure-8 Cable: Figure-8 cables, named for their unique cross-sectional profile, are self-supporting and contain a messenger wire within the jacket. This configuration protects the fiber optic cable from environmental elements, combining lightweight design with high-strength support. The Figure-8 design simplifies installation, making it a popular choice for overhead applications.

Tight-Buffered 900 µm Fiber Optic Drop Cable: Tight buffered drop cable is characterized by its plastic coating, which provides a buffer against external damage. This type of cable is preferred for indoor installations where the cables need to be mechanically spliced to the NID box.

Loose-Tube 250 µm Fiber Optic Drop Cable: Loose tube cable is smaller and filled with a water-resistant gel called “icky pic”. Icky pic provides cushion for the fibers and reduces friction as the optical fiber moves freely within the tube. It is also sensitive to temperature, allowing the gel to expand and contract with temperature changes. This reduces overall stress on the fibers within the cable and gives them year-round durability.

Armored Cable: Interlocking aluminum armor is an option that protects the fiber drop cable from water, ice, and even rodents attempting to chew the fiber optic cable. This armor is an additional material cost to the cable but ensures long term protection. While the initial cost to install armor is technically higher, the durability of armored cable can lower future maintenance costs.

Innerduct: Innerduct is a semi-rigid plastic tubing that can be piped through a building’s interior, giving adequate protection against external factors while avoiding the extra cost of aluminum armor. An added benefit of fiber optic innerduct is that it separates and organizes the different sections of drop cable, simplifying maintenance and eliminating interference.

Selecting the right drop cable hinges on several factors, including installation environment, distance, ease of access, and budget. For example, a burial installation may necessitate a toneable cable for traceability, while an aerial application might benefit from a nontoneable or Figure-8 cable for ease of installation. This includes selecting the correct fiber optic connectors and patch cords for the installation. Ultimately, understanding the unique features and applications of each drop cable type enables network designers and installers to make informed decisions that enhance network performance.

In conclusion, the diversity of ftth drop cable reflects the myriad challenges faced in connecting the last mile of broadband networks. By carefully considering the specific requirements of each installation, stakeholders can ensure that their chosen drop cable will deliver optimal performance and longevity.