- When adding a new building to a campus cabled with 62.5 micron fiber, can the new building be cabled with 50 micron fiber?
This is certainly an issue that is occurring more often in the field. While standards bodies suggest not mixing media in a network, there are certainly cases where it is necessary, for example, when a company is migrating to new technologies or, as in the case of your client, where they are cabling an additional building. There are two ways this can be accomplished: either through an optical connection or through network electronics.
The more straightforward approach is to make the connection between the two media types through the electronics and not in the patch panel. In this scenario, if you are bringing in a 50 micron cable to connect the two buildings there are no issues as long as the 50 micron cable comes into a patch panel and you use 50 micron patch cords to connect straight into the equipment (rather than connecting the 50 micron and 62.5 micron in a patch panel). Bringing the 50 micron cable into the legacy equipment makes good sense and prevents the customer from having potential power budget issues. The launch loss from the electronics into the 50 micron will be higher, but that loss is offset with higher bandwidth, in most cases, so the system works fine. The only other issue is to make sure you have some way of identifying the 50 micron from the 62.5 micron, either through labeling or color coding.
Optical connections are trickier. Although it is technically feasible to combine 50 micron and 62.5 micron core multimode fibers in the same system, there is a one-time attenuation loss when coupling 62.5 micron fiber into 50 micron fiber. This one-time power loss is independent of the number of connectors and fiber type changes that occur in a cable run. Testing by FOLS member companies have shown that this loss is small when there is good coupling alignment and when lasers are used as the transmission source (instead of LEDs). Excess margin in the fiber (or in the transceivers) can, in some instances be used to overcome the extra coupling loss. The optimum solution for a particular system will depend on the system requirements (speed and link length) as well as the type of transceivers used.
- What is Zone Cabling and is it supported by standards?
Zone Cabling is a generic term that means different things to different people. To some, it means an "active consolidation point (CP)" or an "active Multi-User Telecommunications Outlets Assembly (MUTOA)" since the CP and MUTOA are covered in the "zone" clauses of the Pathways & Spaces Standard, TIA-569B. However, active devices in the "zone" are beyond the scope of TIA-568B, Commercial Building Cabling.
What is a Telecommunications Enclosure (TE) and is it supported by Standards?
A telecommunications enclosure (TE) can serve as a second (or third or more) telecommunications room (TR) in certain implementations as described in TIA/EIA 568-B.1 Addendum 5, approved in February 2004.
In a FTTE installation, backbone fiber is run from the entrance facility through the telecommunications room (TR) (which is still required on every floor) to active equipment housed in TEs. The TE acts as a "tiny TR", providing consolidation, distribution, and a point of termination closer to the work area. The final link to the desktop can be via fiber, UTP cable, or wireless.
FTTE takes advantage of the extended distances offered by Centralized Cabling and adds greater flexibility for reconfiguration; critical for applications that require frequent moves, adds & changes (MACs). Current analysis also shows it to be one of the most cost-effective architectures available
- Is OTDR testing necessary for premise cabling?
Since the publication of TIA TSB 140, Additional Guidelines for Field-Testing Length, Loss, and Polarity of Optical Fiber Cabling Systems, many contractors and network owners have questioned whether they should perform Optical Time Domain Reflectometer (OTDR) testing for premises cabling. They also want to know if OTDR testing replaces traditional power meter and light source (PMLS) testing.
First, and most important, OTDR testing does not replace PMLS testing. In fact, the basic fiber certification (Tier 1 test criteria) with a PMLS is the only type of testing required by TIA-568B for premises cabling. This test method measures true end-to-end insertion loss using a light source and a power meter. If the attenuation is within the allotted power budget, the application will work.
OTDR testing, as “Tier 2 test criteria”, does not replace the need for insertion loss measurement, but is an optional test that provides supplementary information such as loss and reflectivity of individual connections, splices and other “events” based on changes in Raleigh backscatter. The results of OTDR testing can help show that the installation meets component specifications and acceptable workmanship quality. An OTDR can also be a useful troubleshooting tool for finding faults in premises cabling. OTDR testing is performed at the discretion of the network owner and system designer.
- Where Can I Find the New Cost Model?
Our third-generation cost model, which provides updated product choices and the ability to customize the ports per floor, is posted on our web site at 2007 Cost Model
The cost model is designed to help users better understand where all-fiber networks offer the lowest cost solution for their networks. IT compares the cost of an all-fiber network to one using vertical fiber/horizontal UTP cabling. The cost model uses generic pricing for comparison but can be fully customized by users to help predict costs for their own networks.
The enhancements to the Cost Model include:
- Updated aggregate pricing that reflects current market conditions. FOLS still encourages users to input their own pricing data to obtain a user specific comparison of network architecture choices. - With an increased usage of OM3 fiber, the fiber option is now 850 nm laser-optimized 50/125 um (OM-3) fiber. - The copper choices now include Category 5e, Category 6, and Category 6a - Users can now customize the port utilization factor by floor or TR to more accurately reflect their own design or use the default settings in the Cost Model. - A graphical Network Architecture comparison allows users to compare costs using pie charts.
- I've read about the new 50-micron laser optimized multimode fiber. When should I specify that instead of standard 50-micron or 62.5 micron fiber?
Companies that are installing fiber today should consider the new 50-micron laser-optimized multimode fiber as it will fully support 10 Mbps or 100 Mb/s legacy applications as well as provide 1 and 10 Gb/s future-proofing. In addition, laser optimized 50-micron multimode fiber supports low-cost multimode opto-electronics and low-cost, easy-to-install connectors.
However, if your company already has 62.5 micron or standard 50-micron installed in its network there's no need to panic -- or to pull out the fiber and recable. Both of these fiber types offer the ability to support application up to Gigabit levels and are likely to meet your company's networking needs for many years to come.
