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Black Box Explains...Straight-pinned and crossover cable.

Straight-pinned cable has the most common type of pinning. The send and receive pairs are wired straight-through on either end of the cable.

Crossover cable is generally used for peer-to-peer connections.... more/see it nowThe send and receive pairs are crossed between Connector A to Connector B on either end of the cable. collapse


Black Box Explains…OM3 and OM4.

There are different categories of graded-index multimode fiber optic cable. The ISO/IEC 11801 Ed 2.1:2009 standard specifies categories OM1, OM2, and OM3. The TIA/EIA recognizes OM1, OM2, OM3, and OM4.... more/see it nowThe TIA/EIA ratified OM4 in August 2009 (TIA/EIA 492-AAAD). The IEEE ratified OM4 (802.ba) in June 2010.

OM1 specifies 62.5-micron cable and OM2 specifies 50-micron cable. These are commonly used in premises applications supporting Ethernet rates of 10 Mbps to 1 Gbps. They are also typically used with LED transmitters. OM1 and OM2 cable are not suitable though for today's higher-speed networks.

OM3 and OM4 are both laser-optimized multimode fiber (LOMMF) and were developed to accommodate faster networks such as 10, 40, and 100 Gbps. Both are designed for use with 850-nm VCSELS (vertical-cavity surface-emitting lasers) and have aqua sheaths.

OM3 specifies an 850-nm laser-optimized 50-micron cable with a effective modal bandwidth (EMB) of 2000 MHz/km. It can support 10-Gbps link distances up to 300 meters. OM4 specifies a high-bandwidth 850-nm laser-optimized 50-micron cable an effective modal bandwidth of 4700 MHz/km. It can support 10-Gbps link distances of 550 meters. 100-Gbps distances are 100 meters and 150 meters, respectively. Both rival single-mode fiber in performance while being significantly less expensive to implement.

OM1 and 2 are made with a different process than OM3 and 4. Non-laser-optimized fiber cable is made with a small defect in the core, called an index depression. LED light sources are commonly used with these cables.

OM3 and 4 are manufactured without the center defect. As networks migrated to higher speeds, VCSELS became more commonly used rather than LEDs, which have a maximum modulation rate of 622 Mbps. Because of that, LEDs can’t be turned on and off fast enough to support higher-speed applications. VCSELS provided the speed, but unfortunately when used with older OM1 and 2 cables, required mode-conditioning launch cables. Thus manufacturers changed the production process to eliminate the center defect and enable OM3 and OM4 cables to be used directly with the VCSELS. OM3/OM4 Comparison
850 nm High Performance EMB (MHz/km)

OM3: 2000

OM4: 4700


850-nm Ethernet Distance
1-GbE
OM3: 1000 m

OM4: 1000 m


10-GbE
OM3: 300 m

OM4: 550 m


40-GbE
OM3: 100 m

OM4: 150 m


100-GbE
OM3: 100 m

OM4: 150 m

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Black Box Explains...Category 6.

Category 6 (CAT6)–Class E has a specified frequency of 250 MHz, significantly improved bandwidth capacity over CAT5e, and easily handles Gigabit Ethernet transmissions. In recent years, it has been the... more/see it nowcable of choice for new structured cabling systems. CAT6 supports 1000BASE-T and, depending on the installation, 10GBASE-T (10-GbE).

10-GbE over CAT6 introduces the problem of Alien Crosstalk (ANEXT), the unwanted coupling of signals between adjacent pairs and cables. Because ANEXT in CAT6 10-GbE networks is so dependent on installation practices, TSB-155 qualifies 10-GbE over CAT6 up to 55 meters and requires it to be 100% tested. To mitigate ANEXT in CAT6, it is recommended that you unbundle the cables and increase the separation between the cables.

You can always contact Black Box Tech Support to answer your cabling questions. Our techs can recommend cable testers and steer you in the right direction when you’re installing new cabling. And the advice is FREE! collapse


Black Box Explains…Component vs. channel testing.

When using a Category 6 system, the full specification includes the testing of each part individually and in an end-to-end-channel. Because CAT6 is an open standard, products from different vendors... more/see it nowshould work together.

Channel testing includes patch cable, bulk cable, jacks, patch panels, etc. These tests cover a number of measurements, including: attenuation, NEXT, PS-NEXT, EL-FEXT, ACR, PS-ACR, EL-FEXT, PS-ELFEXT, and Return Loss. Products that are tested together should work together as specified. In theory, products from all manufacturers are interchangeable. But, if products from different manufacturers are inserted in a channel, end-to-end CAT6 performance may be compromised.

Component testing, on the other hand, is much stricter even though only two characteristics are measured: crosstalk and return loss. Although all CAT6 products should be interchangeable, products labeled as component are guaranteed to perform to a CAT6 level in a channel with products from different manufacturers.

For more information on cable, channel, and component specs, see below.

Buyer’s Guide: CAT5e vs. CAT6 Cable

Standard — CAT5e: TIA-568-B.2; CAT6: TIA-568-B.2-1

Frequency — CAT5e: 100 MHz; CAT6: 250 MHz

Attenuation (maximum at 100 MHz) —
Cable: CAT5e: 22 dB; CAT6: 19.8 dB
Connector: CAT5e: 0.4 dB; CAT6: 0.2 dB
Channel: CAT5e: 24.0 dB; CAT6: 21.3 dB

NEXT (minimum at 100 MHz) —
Cable: CAT5e: 35.3 dB; CAT6: 44.3 dB
Connector: CAT5e: 43.0 dB; CAT6: 54.0 dB
Channel: CAT5e: 30.1 dB; CAT6: 39.9 dB

PS-NEXT (minimum at 100 MHz) — 32.3 dB 42.3 dB

EL-FEXT (minimum at 100 MHz) —
Cable: CAT5e: 23.8 dB; CAT6: 27.8 dB
Connector: CAT5e: 35.1 dB; CAT6: 43.1 dB
Channel: CAT5e: 17.4 dB; CAT6: 23.3 dB

PS-ELFEXT (minimum at 100 MHz) — CAT5e: 20.8 dB; CAT6: 24.8 dB

Return Loss (minimum at 100 MHz) —
Cable: CAT5e: 20.1 dB; CAT6: 20.1 dB
Connector: CAT5e: 20.0 dB: CAT6: 24.0 dB
Channel: CAT5e: 10.0 dB; CAT6: 12.0 dB

Characteristic Impedance — Both: 100 ohms ± 15%

Delay Skew (maximum per 100 m) — Both: 45 ns

NOTE: In Attenuation testing, the lower the number, the better. In NEXT, EL-FEXT, and Return Loss testing, the higher the number, the better. collapse


Black Box Explains...Ceramic and composite ferrules.

Cables manufactured with ceramic ferrules are ideal for mission-critical applications or connections that are changed frequently. These cables are high quality and typically have a very long life. Ceramic ferrules... more/see it noware more precisely molded and fit closer to the fiber than their composite counterparts, which gives them a lower optical loss.

On the other hand, cables with composite ferrules are ideal for less critical applications or connections that won’t be changed frequently. Composite ferrule cables are characterized by low loss, good quality, and long life. collapse


Black Box Explains...Fiber optic cable construction.

Fiber optic cable consists of a core, cladding, coating, strengthening fibers, and cable jacket.

Core
This is the physical medium that transports optical data signals from an attached light source to... more/see it nowa receiving device. The core is a single continuous strand of glass or plastic that’s measured (in microns) by the size of its outer diameter. The larger the core, the more light the cable can carry.

All fiber optic cable is sized according to its core’s outer diameter.

The three multimode sizes most commonly available are 50, 62.5, and 100 microns. Single-mode cores are generally less than 9 microns.

Cladding
This is a thin layer that surrounds the fiber core and serves as a boundary that contains the light waves and causes the refraction, enabling data to travel throughout the length of the fiber segment.

Coating
This is a layer of plastic that surrounds the core and cladding to reinforce the fiber core, help absorb shocks, and provide extra protection against excessive cable bends. These buffer coatings are measured in microns (µ) and can range from 250 to 900 microns.

Strengthening fibers
These components help protect the core against crushing forces and excessive tension during installation.

The materials can range from Kevlar® to wire strands to gel-filled sleeves.

Cable jacket
This is the outer layer of any cable. Most fiber optic cables have an orange jacket, although some types can have black or yellow jackets. collapse


Black Box Explains...Fiber connectors.

• The ST® connector, which uses a bayonet locking system, is the most common connector.

• The SC connector features a molded body and a push- pull locking system.

• The FDDI... more/see it nowconnector comes with a 2.5-mm free-floating ferrule and a fixed shroud to minimize light loss.

• The MT-RJ connector, a small-form RJ-style connector, features a molded body and uses cleave-and-leave splicing.

• The LC connector, a small-form factor connector, features a ceramic ferrule and looks like a mini SC connector.

• The VF-45™connector is another small-form factor connector. It uses a unique “V-groove“ design.

• The FC connector is a threaded body connector. Secure it by screwing the connector body to the mating threads. Used in high-vibration environments.

• The MTO/MTP connector is a fiber connector that uses high-fiber-count ribbon cable. It’s used in high-density fiber applications.

• The MU connector resembles the larger SC connector. It uses a simple push-pull latching connection and is well suited for high-density applications.
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