Industrial > Cabling & Infrastructure

The news on bandwidth
The need for increased bandwidth never ceases—the more you have, the more you need. Applications keep getting more complex, and files keep getting bulkier. It won’t be long before you need to increase the speed of your network.

Don’t worry. Black Box experts are ready 24 hours a day to answer your questions. When you click on “Talk to a Tech,” you’ll be talking to a trained expert in seconds. If you need help installing a network, or adding an additional drop, contact us.

Because unshielded twisted-pair UTP cable is by far the most common networking cable, let’s take a brief look at where UTP is headed.

The limits of Category 5
Category 5 (CAT5) cabling is good, solid cable for 100-Mbps LANs. The Category 5 standard has been around since 1991, so it’s well established. You’ll find existing Category 5 installations everywhere. What can Category 5 cable do, and what can’t it do?

If you still have a lot of 10-Mbps equipment, CAT5 cabling will serve your needs. It also handles 100-Mbps Fast Ethernet transmissions very well.

But if you’re running up against the performance limits of a 100-Mbps network, you’ll probably want to upgrade at least parts of your system fairly soon to Category 5e (CAT5e) or higher.

Category 5e: the improved Category 5
Category 5e, also known as Enhanced Category 5, or CAT5e, was ratified in 1999. It’s an incremental improvement designed to enable cabling to support full-duplex Fast Ethernet operation and Gigabit Ethernet.

The main differences between CAT5 and CAT5e can be found in the specifications. The performance requirements have been raised slightly in the new standard.

CAT5e has stricter specifications for Power Sum Equal-Level Far-End Crosstalk (PS-ELFEXT), Near-End Crosstalk (NEXT), Attenuation, and Return Loss (RL) than those for CAT5. Like CAT5, CAT5e is a 100-MHz standard, but it has the capacity to handle bandwidth superior to that of CAT5. With these improvements, you can expect problem-free, full-duplex, 4-pair Ethernet transmissions over your CAT5e UTP.

Category 6
The next level in the cabling hierarchy is Category 6 (CAT6) (ANSI/TIA/EIA-568-B.2-1), which was ratified by the TIA/EIA in June 2002. CAT6 provides higher performance than CAT5e and features more stringent specifications for crosstalk and system noise.

The quality of the data transmission depends upon the performance of all the components of the channel. So to transmit according to CAT6 specs, the jacks, patch cables, patch panels, cross-connects, and cabling must all meet CAT6 standards. (The channel includes everything from the wallplate to the wiring closet.) The CAT6 components are tested individually, and they are also tested together for performance. In addition, the standard calls for generic system performance so that CAT6 components from any vendor can be used in the channel.

CAT6 channel transmission requirements should result in a Power-Sum Attenuation-to-Crosstalk Ratio (PS-ACR) that’s greater than or equal to zero at 200 MHz.

In addition, all CAT6 components must be backward compatible with CAT5e, CAT5, and CAT3. If different category components are used with CAT6 components, then the channel will achieve the transmission performance of the lower category. For instance, if CAT6 cable is used with CAT5e jacks, the channel will perform at a CAT5e level.

Industry standards
The advantage of sticking to the industry standards is the knowledge that your cabling will be compatible with standards applications. But the standards are always being improved upon, and it takes time to ratify a new standard. Often, as with CAT6, the final standard may be different from the proposed standard. For the latest information, contact our FREE Tech Support.

Twisted-Pair Cable Specifications Comparison
Frequency — CAT5, CAT5e: 100 MHz;
CAT6: 250 MHz;
CAT7 (Proposed): 600 MHz
Attenuation (min. at 100 MHz) — CAT5, CAT5e: 22 dB;
CAT6: 19.8 dB;
CAT7 (Proposed): 20.8 dB
Characteristic Impedance — All: 100 ohms ± 15%
NEXT (min. at 100 MHz) — CAT5: 32.3 dB;
CAT5e: 35.3 dB;
CAT6: 44.3 dB;
CAT7 (Proposed): 62.1 dB
PS-NEXT (min. at 100 MHz) — CAT5: no specification;
CAT5e: 32.3 dB;
CAT6: 42.3 dB;
CAT7 (Proposed): 59.1 dB
ELFEXT (min. at 100 MHz) — CAT5: no specification;
CAT5e: 23.8 dB;
CAT6: 27.8 dB;
CAT7 (Proposed): not yet specified
PS-ELFEXT (min. at 100 MHz) — CAT5: no specification;
CAT5e: 20.8 dB;
CAT6: 24.8 dB;
CAT7 (Proposed): not yet specified
Return Loss (min. at 100 MHz) — CAT5: 16 dB;
CAT5e: 20.1 dB;
CAT6: 20.1 dB;
CAT7 (Proposed): 14.1 dB
Delay Skew (max. per 100 m) — CAT5: no specification;
CAT5e: 45 ns:
CAT6: 45 ns;
CAT7 (Proposed): 20 ns

RS-232, also known as RS-232C and TIA/EIA-232-E, is a group of electrical, functional, and mechanical specifications for interfaces between computers, terminals, and modems. The RS-232 standard was developed by the Electrical Industries Association (EIA), and it defines requirements for connecting data communications equipment (DCE)—modems, converters, etc.—and data terminal equipment (DTE)—computers, controllers, etc.) devices.

The standard, which is functionally equivalent to ITU V.24/V.28, specifies the workings of the interface, circuitry, and connector pinning. Both sync and async binary data transmission fall under RS-232. Most PCs use the RS-232 interface to transmit data to modems, and some printers even use it.

Although RS-232 is a “standard,” you cannot necessarily expect seamless communication between two RS-232 devices. Why? Because different devices have different circuitry or pinning, and different wires may be designated to perform different functions.

The typical RS-232 connector is DB25, but some PCs and other data communication devices have DB9 connectors. To connect 9-pin PC ports to devices with 25-pin connectors, you need a simple adapter cable. The most commonly used interface, RS-232 is ideal for transmitting data at speeds up to 20 kbps and over distances up to 50 feet (15.2 m).

Multimode, 50- and 62.5-micron cable.
Multimode cable has a large-diameter core and multiple pathways of light. It comes in two core sizes: 50-micron and 62.5-micron.

Multimode fiber optic cable can be used for most general data and voice fiber applications, such as bringing fiber to the desktop, adding segments to an existing network, and in smaller applications such as alarm systems. Both 50- and 62.5-micron cable feature the same cladding diameter of 125 microns, but 50-micron fiber cable features a smaller core (the light-carrying portion of the fiber).

Although both can be used in the same way, 50-micron cable is recommended for premise applications (backbone, horizontal, and intrabuilding connections) and should be considered for any new construction and installations. Both also use either LED or laser light sources. The big difference between the two is that 50-micron cable provides longer link lengths and/or higher speeds, particularly in the 850-nm wavelength.

Single-mode, 8–10-micron cable.
Single-mode cable has a small, 8–10-micron glass core and only one pathway of light. With only a single wavelength of light passing through its core, single-mode cable realigns the light toward the center of the core instead of simply bouncing it off the edge of the core as multimode does.

Single-mode cable provides 50 times more distance than multimode cable. Consequently, single-mode cable is typically used in long-haul network connections spread out over extended areas, including cable television and campus backbone applications. Telcos use it for connections between switching offices. Single-mode cable also provides higher bandwidth, so you can use a pair of single-mode fiber strands full-duplex for up to twice the throughput of multimode fiber.

Specification comparison:

50-/125-Micron Multimode Fiber

850-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 3.5 dB/km;
Distance: 550 m;

1300-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 1.5 dB/km;
Distance: 550 m

62.5-/125-Miron Multimode Fiber

850-nm Wavelength:
Bandwidth: 160 MHz/km;
Attenuation: 3.5 dB/km;
Distance: 220 m;

1300-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 1.5 dB/km;
Distance: 500 m

8–10-Micron Single-Mode Fiber

Premise Application:
Wavelength: 1310 nm and 1550 nm;
Attenuation: 1.0 dB/km;

Outside Plant Application:
Wavelength: 1310 nm and 1550 nm;
Attenuation: 0.1 dB/km

With breakout- or fanout-style cables, the fibers are packaged individually. A breakout cable is basically several simplex cables bundled together in one jacket. Breakout cables are suitable for riser and plenum applications, and conduit runs.

This differs from distribution-style cables where several tight-buffered fibers are bundled under the same jacket.

This design of the breakout cable adds strength to the cable, although that makes it larger and more expensive than distribution-style cables.

Because each fiber is individually reinforced, you can divide the cable into individual fiber lines. This enables quick connector termination, and eliminates the need for patch panels.

Breakout cable can also be more economical because it requires much less labor to terminate.

You may want to choose a cable that has more fibers than you actually need in case of breakage during termination or for future expansion.