The Fiber Optic Association, Inc.

 

FOA Connector Standard

 

FAQs

 

Why Are There So Many Fiber Optic Connectors?

The early days of fiber optics were times of fast changing technologies. New ideas popped up all the time. The earliest connecctor, the Deutsch 1000, had a bare fiber inside a large stainless body and used a plastic conical alignment fixture with index -matching fluid. The AT&T Biconic used a molded plastic ferrule, as did the AMP Optimate. The Amphenol 905 used a machined stainless ferrule. Finally, in the mid-80s, the Japanese developed the 2.5 mm ceramic ferrule which worked much better. It was widely adopted and used since with little change, but in numerous different body designs like the FC, ST, SC, FDDI, ESCON and OptiJack.

In the late 90s, several manufacturers came our with "Small Form Factor Connectors." They were designed to be, well, small. Most were simply shrunken connectors with ceramic ferrules, except for the MT-RJ which used a molded rectangular ferrule and the 3M Volition which went back to the Deutsch bare fiber idea.

A SFF "standard" never happened in TIA TR 42.8 because it required a choice between designs from several manufacturers and none of them wanted to agree to a standard from a competitor. The TR 42.8 committee got a lot of criticism because of that episode, mostly from users and equipment manufacturers who wanted a single standard.

In the period following, none of those connectors has emerged as a defacto standard. Not having a standard connector has been a major detriment to fiber penetration to the desktop.

 

Why Do We Need A STANDARD Connector?

In premises cabling, fiber is always competing with copper wiring that has one connector and one cable (only in many different grades or Categories.) Users considering fiber optics are expecting a "standard" and are not happy with the proliferation of fiber optic connector choices offered to them. Applications like Fiber To The Desk would be so much easier to sell if there were only one choice, so let's get rid of that objection. And standards lead to lower costs, the other big issue for FTTD applications!

We're really talking about a connector for user patchcords, connecting wall outlets and patch panels to networking equipment. What goes on behind the patch panel is not an issue, so we can assume it's a patchcord connector.

We're not concerned with the outside plant applications, as telcos are going to do whatever they want anyway.

 

What Kind Of Connector Are We Suggesting?

We're suggesting a standard small duplex connector created with some hard guidelines:
a. It must be able to be manufactured cheaply using well-proven technology and parts
b. It must be easily terminated using standard technology
c. It must be testable using industry standards. (Did you follow the progress of 568's TSB-140 on fiber optic testing? It missed its mark because no one could explain how to test certain connectors that are not mateable with commonly used test equipment!)
d. It must be easily accommodated by transceivers, patch panels, and networking equipment.
e. The design specification must be "open source" - available to anyone without licenses.

 

Can We Be More Specific?

Do you remember the FDDI and ESCON connectors? They were duplex connectors for specific networks. We're thinking along the same lines but smaller, e.g. using 1.25 mm ferrules in a plastic body the same size as a RJ-45 with a similar spring latch. Ideally, it would have ferrule spacing of 6.25 mm and depth specs the same as a duplex LC so it would allow manufacturers to easily tool for it, especially for transceivers. It would also allow using hybrid adapters to mate it with LCs, MUs and LX-5s. So you could have a patch panel with FOA connectors on the user side and LCs or MUs on terminated cables.

 

Why Not Just Use A Duplex LC? MT-RJ Or Optijack?

A duplex connector like the LC is a great connector, but it requires zipcord when you make a patchcord and is bulky with the clip that holds two of them together. It looks like two connectors clipped together, not a duplex connector. What we hear is a smaller, neater connector using the new smaller cable designs is more acceptable.

The MT-RJ is a much cleaner, more integrated, even aesthetic design, that can use smaller 1.6 and 2 mm cables, but the ferrule has been the cause of many issues, including creating great difficulty for test equipment manufcaturers interfacing to it and users testing them properly.

We like the design of the OptiJack, but with the 2.5 mm ferrules at the chosen spacing, it is only compatible to its own jack, not the SC, FC or ST which use the same ferrule, which was an advantage of the FDDI and ESCON connectors.

 

 

The FOA Is Not Designing A Connector!

Please understand that the FOA has no intention of designing a connector and trying to force manufacturers to make it - we know that has no chance of success! What we are doing is taking the input from our end user contacts and feedback from some of our 13,000 CFOT certified technicians and creating an idea for a connector that would be a simple product to design or adapt hardware to, makes good sense and would be acceptable to many manufacturers because of that and it is not a competitor's product.

 

Why Use The 1.25 mm ferrule?
The 1.25 mm ferrule is compatible with both singlemode and multimode fibers, is more precisely made, has a shape that is easier to polish and is compatible with any adhesive or other termination type. In addition, the small ferrule size makes it easier to design a small connector body as the ferrule takes up less space.
Using the 1.25 mm ferrule means it will be possible to have hubrid mating adapters that can allow mating the FOA connector to the LC, MU and LX-5, as well as any other connector designed around the same ferrule.
In addition, feedback from the industry indicates the LC is overtaking the SC in usage, meaning the smaller ferrules will be less expensive - they even use less material too, if that's really a significant factor in cost.

What Are We Doing Differently?

The FOA proposal is a different approach. Our board members are quite experienced with fiber optic connectors and understand the issues of technology and design quite well. We're especially aware of the difficulty of terminating and testing some of the current connectors. We feel we are competent to provide design guidelines for a new and unique connector design that will not suffer the same fate as the proprietary designs offered in the SFF because we are not a connector manufacturer - we're not involved in products at all, in fact.

 

What Exactly Is The FOA?

The FOA is a nonprofit educational organization chartered to promote fiber optics through education, certification, standards, or any other appropriate means. Since our founding in 1995, we have established a certification program that has been used by over 125 schools to certify over 13,000 CFOTs (Certified Fiber Optic Technicians.) Organizations like NASA and Cisco use our certification programs. We are promoting education by creating introductory programs for teachers in secondary and technical schools and posting them for free on our website. Over 5000 teachers have downloaded our free introduction to fiber optics program for their classes. We have just started a comprehensive "Train The Trainer" online program to supplement our annual TTT seminars - also free to any instructor interested in creating and teaching a fiber optic program.

This year, we decided to become involved more in standards programs. We had already worked with NECA and ANSI to create a fiber optic installation standard (NECA/FOA-301) and were monitoring and commenting on several TR42.8 and FO-4 projects. I have begun attending standards meetings, at first concentrating on TR 42.8 because work is just beginning on the "C" revision of TIA-568. At the June meeting in Providence, I presented a number of suggested changes, some quite substantial, for consideration in the C revision of 568. It will probably take at least 2 years for this rev to work its way through the system.

The FOA has no members - individual or corporate. We're just a nonprofit promoting fiber optics in ways we deem appropriate. We have not tried to get support for the idea before going public, as we do not want to be seen as representing any faction in this issue, we're just trying to do what's best for the industry, especially in combating the stranglehold that copper has on the desktop.

 

What are we planning to do?

 

1) Introduce the concept to the industry.

 

2. Contact component manufacturers, esp. transceiver manufacturers, to get their reaction to our proposal for a standard connector. They seem to be very interested in this project, because now they have to make so many different physical interfaces to their products.

 

3. Get input from networking standards committees. They have also expressed disappointment at the SFF standardization failure.

 

4. Create a design guideline. We do not plan to design a connector, just the interface specifications, e.g. ferrule size, spacing and alignment, and latching mechanism. We do not want to cross into patent or intellectual property issues if at all possible. This guideline should be simple enough to insure interoperability while allowing latitude for manufacturers to design connectors that fit the interface spec and offer unique features like ferrule shrouding. And it should be inexpensive development since it uses available parts and technology.

 

5. Let the industry and the market tell the manufacturers that this is important to them and they want a standard product. Manufacturers will do what the market wants. I have already heard from my contacts in several connector manufacturers that they already know this is an important issue and they believe we may have the proper way to establish a workable standard.

 

6. Either through one of the current standards committees or through one we convene ourselves, invite all interested parties to join the design process and provide their expertise to make this a workable concept. From this stage, we create a FOCIS document (Fiber Optic Connector Interface Standard).

 

7. Allow manufacturers to bring the product to market.

 

Are We Nuts?

We at the FOA know how hard this process will be, but we believe it's worth the effort. When people and companies understand that we are altruistic - really doing this because the industry needs it - and the FOA may well be the only organization that has the knowledge, independence and desire to make it happen, we expect to be taken seriously. And we have been.

 

Will The FOA Connector Proposal Be Compatible With Any Other Connectors?

The proposed design is compatible with LC and MU connectors that use the same ferrule. Mating adapters should be easy to produce that allow intermateability.

 

 

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