Factory Terminated vs. Field Terminated Fiber Optic Cable Assemblies

Building a fiber optic cable system for your business or facility requires a few very unique decisions. Fiber optics provides a superior data transmission network that cannot be interrupted by electronics or wireless signals. For cable companies, fiber enables you to provide 10G signal strength and minimal latency for streaming media services. Among the biggest challenges faced by cable companies is fiber network installation.

Find out how GPON works in our blog post: Why is GPON the Best Fiber-Optic Technology?

In the Cable’s Fiber Outlook Survey Report, 81% of survey respondent companies predicted that the cost of installation and labor as a major challenge to upgrading the service network. Upgrading the network means integrating fiber with other types of cable, which means termination. The type of fiber termination you use, factory or field terminated, determines both signal clarity and speed of installation. 

Field Terminated or Factory Terminated Fiber Optics?

Any experienced technician can understand why cable connectorization (the act of applying a connector to the cable end) is so important. It all depends on whether technicians are applying fiber optic connectors in the field as they lay the cable or if you are using cables with factory-applied connectors. In industry terms, this is known as Field Termination (DIY connecting on-site) and Factory Termination (factory-installed connectors).

Which connector type is best for your cable company’s fiberoptic assembly? Read on to find out how to make the right decision. 

Priorities of Fiber Optic Cable Selection

Over half of cable company survey respondents reported plans to use fiber for symmetrical multi-gigabit speeds, IoT, and streaming video which means the need for top-quality signal transfer. When building a fiber optic cable assembly, there are a few top priorities to consider. No matter what data you’re transmitting or how large a system you are building, cable and connector selection matters a great deal in fiber optics.

  • Reduce Insertion Loss and Return Loss

Every fiber optic’s first priority is reducing insertion loss and return loss, also known as IL and RL for short. Both types of loss are caused by an imperfect cable tip or connector attachment at the end of each fiber optic cable. If the cable is marred or smudged, or if the connector is loose, then data will be lost at that connector point.

  • Exact Length

Running data cable should always be done carefully and precisely so that connectors are available exactly where they are needed without too much slack in between, and some room to move around. This balance requires either exact measurements or on-site cutting to the most convenient length.

  • Routable Through Cable Tracks

The cable you choose also must smoothly run through your cable tracks, however large or shared they may be. This seems like a minor concern until you find yourself with a cable that doesn’t fit or run easily. 

Field Terminated Fiber Optic Cables

When installing your cable company’s fiber infrastructure, the most common way to install fiber optic cables is with spools of un-connectorized fiber optic wire. 56% of cable companies are installing fiber in primarily greenfield (new infrastructure) areas. This is often done with field-terminated cables. With field-termination, technicians run however much fiber cable they need, clip it at the right points and apply connectors in the field using skill and a special kit. In this kit are the high-quality, high-precision tools and supplies they need to properly apply a fiber optic connector with low insertion loss.


  • Cable Length Flexibility & Precision
  • Easy Cable Routing
  • Standard Procedure

Pros of Field Terminated Assemblies

If you’re running cable and don’t have a good way to estimate the distance, field termination is your best bed. You can run as much or as little cable as you need without risk of coming up short or having too much slack.  The cables are also sleek without bulky ends and are therefore easier to run through cable tracks. Field termination also has the benefit of being the standard way that fiber optic cable assemblies are installed. But there are downsides. 


  • Time Consuming
  • Requires a Kit
  • Quality Depends on Skill and Components
  • Consumes Materials
  • Can Fail Testing and Must be Redone

Cons of Field Terminated Assemblies

Field termination has the advantage of flexibility, but it also has all the disadvantages of in-field work. It requires a fully stocked and highly specialized kit of tools and supplies including strippers, scissors, epoxy, polishing paper and compound, and crimping tools. Not to mention the connectors themselves and the microscope testing required to confirm a job done well.

Fiber Optic Field Termination Process

  • Strip the Cable
  • Prep the Epoxy
  • Apply the Connector
  • Polish
  • Inspect Visually & Microscopically
  • Test Connection

Field termination takes time, sometimes as much as 30 minutes per connector, and they don’t always pass the final test. Because the skill and precision of the technician determine the quality of the connection, sometimes the whole process must be done over more carefully. The cost slowly stacks up supplies and quickly stacks in technician hours.

Factory Terminated (Pre-Terminated) Fiber Optic Cables

If your cable company knows exactly how long each fiber cable should be, then factory terminated cables are incredibly useful and more reliable than field-termination. Factory-termination is especially useful for the 25-40% of cable companies installing brownfield areas and precisely planned spaces. Factory termination is often also referred to as pre-terminated cables. These come in pre-measured lengths with the fiber optic connectors already installed with factory-level precision and quality assurance. But it’s logistical limitations explain why field termination is still widely used.


  • Factory Polish Quality
  • Minimum Possible Insertion Loss
  • Always Passes Testing

Pros of Factory Terminated Assemblies

When you’re using a factory-installed fiber optic connector, you know it’s good quality. When a factory installs a connector, the cut is always exactly right, the polish is machine-perfect, and the epoxy is cured exactly long enough. There are no blemishes, smudges, or specs of dust on the cable end inside the connector which means the minimum possible insertion loss in the connector data transition. The factory also takes care of its own quality assurance in inspecting the polish, connection, and final insertion loss rate before any cable is shipped.

In an industry where 76% of cable companies are not fully confident in technician abilities to handle fiber, factory-terminated cables are the safest way to ensure the best possible signal quality. But there are some notable limitations. 


  • Must-Know Lengths Exactly
  • Can be Too Bulky for Cable Tracks

Cons of Factory Terminated Assemblies

In order to use a fiber optic cable with both ends pre-terminated in the factory, you must have your cable length measurements exact, with enough room to allow for minor changes in the final configuration. Order too long a cable, and you’ll have unwanted slack. Order too short a cable, and you can’t make the connection. So for any system that needs flexible cable length determination, field termination is the only option. Pre-terminated cables also rarely come in lengths longer than 100 feet.

The other considerable problem with factory terminated fiber optic cable is that it may not run easily through your cable tracks. Though they come with eye-pulls, the bulky connector may catch in your cable paths. 

When to Use Field Terminated vs Factory Terminated Fiber Optic Cables

Factory terminated cables are undeniable of higher quality and provide more reliable performance than field termination. But the sizing and cable track limitations mean that their applications are limited. The best assembly for factory terminated cables is surrounding control panels and in smaller data transmission areas. Anywhere that you are using shorter cables with easily pre-determined lengths, factory-terminated cables are your best bet. Neighborhood cable company installations may benefit from factory-terminated cables where exact lengths can be measured and implemented, easing survey-respondent worries about training technicians to properly connectorize.

Field-terminated cables are best used when you have to run fiber optics over very long distances or through tracks that you cannot easily measure. Sometimes, a measuring cable can be used to determine the length of pre-terminated cable, but you cannot always count on this method. Field terminated cables provide flexibility and are more easily transitioned through pigtails.

It’s also important to know that a hybrid cable is often the best choice. You can get spools of cable with one factory terminated end and one end ready for field termination. This way, you get the benefit of at least one perfectly connected fiber optic cable end, along with the flexibility and cable-track access of an un-connectorized end to be completed on-site.

What are the best fiber implementation methods for your cable company? Based on the Cable’s Fiber Outlook Survey Report, many cable companies are approaching fiber but the best installation method changes with each situation. Fiberoptic cables are transforming the speed of the internet and media signals across the world. As more and more service networks upgrade to fiber, you will see data speeds rapidly increase, as well as a reduction to signal interruptions from environmental factors.

When installing fiberoptic cables, the type of termination will determine the time it takes to install each end and potentially the signal quality in translation from electrical signals to light and back again.

Find out how GPON works in our blog post: Why is GPON the Best Fiber-Optic Technology?

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