Thursday, August 5, 2010

How To Find Underground Wires & Valves Using Greenlee 521A

1) Headset
2) Ground Stake
3) Transmitter
4) Receiver
5) Carrying Case
6) Black Lead
7) Red Lead
8) Selector Knob
9) ON/OFF Switch
10) Battery Cover

Batteries (included)
• Transmitter: Qty 8 - "D" batteries
• Receiver: Qty 1 - 9v alkaline battery

Note: The transmitter produces high voltage. Turn the transmitter off before handling the output leads. Disconnect all wires from the controller when fault locating. Turn the selector knob to the BATTERY TEST position. The meter should read between 8 and 10.

Before starting, you must ensure the transmitter is set up properly.

IMPORTANT: To ensure that the 521A transmitter is producing optimum signal, connect the red and black leads together and turn the unit on. Turn the selector knob to position #5. The meter needle should rise to at least a 10 reading.

1. With the transmitter off, connect the red lead to the wire to be located and the black lead to a good earth ground with the stake provided. (Refer to Figure 1). If the clock is indoors, the earth ground stake MUST be grounded at the point where the wires exit the building. It might require running a length of wire to the
outside. Do not use a common ground inside (i.e., electrical or water pipe).

2. Now turn the transmitter on and start rotating the selector knob clockwise.
Once you leave the BATTERY TEST position and go to #1, the meter needle will fall off to near zero. As you increase the output, the needle will rise slightly with each advancement. Stop when the meter reads between 4 and 8. The transmitter is now set for maximum efficiency for this job. If a reading of 4 is not obtainable, you may not have enough of a ground fault to locate the wire.

Soil condition can also affect the efficiency of the unit. Moisture is a good conductor, so the wetter the soil, the better. In dry or sandy conditions you may experience signal loss. Add some water near the ground stake to improve results.

3. Plug the headset into the receiver if desired, turn it on and point the antenna or probe end at the transmitter. A pulsing tone should be heard through the headset and an indication should register on the receiver meter.


Locating Wire Path
With the probe pointed toward the ground, walk completely around the transmitter location. An absence of tone or null will be detected directly over the path of the wire. Movement to either side will cause the volume of tone signal intensity to increase. Follow the null to determine the wire path. (Refer to Figure 2.)

Finding Wire Breaks and Nicks
When attempting to find breaks and nicks, you should decrease the sensitivity of the receiver when pointing it off to either side of the null. You will be able to notice the change in signal intensity immediately. Do not allow the meter to peg or go above 10. This will greatly help in the fault locating process.
Note: The wire must have a path to ground to be successfully located. These paths exist in a great majority of all direct buried wires due to insulation imperfections, nicks, and bad splices. If not, create one by grounding the remote end.
• The end of a cut or broken wire can be located by following the path until the null disappears and gives way to a hot spot. Beyond the hot spot, no null can be detected. Back up until the null is detected, and this will be the approximate end of the broken wire. (Refer to Figure 3.)
• Larger nicks in the wire can be located in almost the same way as locating opens. Follow the null and strong signal along the sides of the wire until the signal becomes very weak along the sides of the null. This will occur within a relatively short distance. The transmitted signal bleeds to ground at the nick and then wants to return to the ground stake along the outside of the wire itself. The majority of signals will stop at the nick indicated by the low receiver reading just beyond the nick. (Refer to Figure 4.)
• To more accurately define the location of an open or larger nick (ground fault), position the receiver tip on the ground near the point where the last strong signal was detected along the side of the path. The receiver tip should be pointing at the ground and be approximately 6 inches to either side from the null. Because you are so much closer to the path, the sensitivity knob must be adjusted down until the meter reads just below 10.

While maintaining the 6-inch distance from the null, move the receiver down the line, paying close attention to the meter reading. Once you pass the open or nick, the meter will fall off rapidly.

Determining Depth of Wire
To determine the depth of the wire, first mark the ground directly over the path. Turn the receiver sideways to the path, and tip it 45 degrees. Move the receiver away from the path, maintaining the 45-degree tip until a null is detected. Mark this spot. The depth is the distance between the two marks. (Refer to Figure 5.)

Two-Step Solenoid Valve Locating Process
Solenoid valves can easily be located provided all the wires leading to them are intact and the solenoid itself is still good.
Step 1. Start at the clock. Connect the red transmitter lead to the station wire leading to the subject valve, and connect the black lead to earth ground. Turn the transmitter on, adjust the output to the highest level, assemble the receiver, locate the path, and start tracing the wire following the null. The null will be present until you pass over a solenoid valve, and then the signal will become extremely strong. Mark this spot. Check around this hot spot for a null leaving the area. If the null continues, follow it and mark any additional hot spots. (Refer to Figure 6.) If only one hot spot or valve is located, it will be the valve in question.
Step 2. If more than one hot spot is found, mark them and return to the transmitter and turn it off. Lift the black lead from the ground stake and connect it to the common wire. Turn the transmitter on, set the selector knob to the highest reading, and return to the first hot spot with the receiver. Touch the tip of the receiver antenna to the ground in the center of the first hot spot and set the sensitivity knob to read near mid-scale. Now go to the second spot and without touching the sensitivity knob, check the strength of the signal at each hot spot and determine which, out of all of them, is the strongest signal. This is the valve for the station wire you are connected to.

Greenlee 521A Maintenance

Battery Replacement
1. Turn the unit off.
2. Remove the battery cover.
3. Replace the batteries (observe polarity).
4. Replace the battery cover.

Periodically wipe with a damp cloth and mild detergent; do not use abrasives or solvents.

Questions? Leave them below. Thanks!

Monday, July 19, 2010

HDMI Mini vs HDMI Micro

HDMI Mini vs HDMI Micro

So what's the difference between the HDMI mini connector and HDMI micro connector? Let's look at some of the specs.

HDMI Mini Connector:

- Type C HDMI
- 10.42 mm × 2.42 mm
- Defined in the HDMI 1.3 specification
- 19-pin configuration

HDMI Micro Connector:

- Type D HDMI
- 6.4mm x 2.8 mm
- Defined in the HDMI 1.4 specification
- 19-pin configuration

As you can see, they both employ the 19-pin configuration, but the Mini HDMI (Type C) is different because all positive signals of the differential pairs are swapped with their corresponding shield, the DDC/CEC Ground is assigned to pin 13 instead of pin 17, the CEC is assigned to pin 14 instead of pin 13, and the reserved pin is 17 instead of pin 14. The Micro (Type D) uses the same pin configuration as the standard HDMI (Type A).

Mini HDMI (Type C) to Standard HDMI (Type A) cables are generally used for connecting your HD camcorder to your HDTV.

Micro HDMI (Type D) to Standard HDMI (Type A) cables are used for connecting smart phones like the Motorola Droid X and Sprint HTC Evo to HDTVs.

Video shows the Motorola Droid X getting hooked up to an HDTV via the HDMI Micro cable:

Friday, June 11, 2010

How It's Made: Fiber Optic Cable

Corning has been a leading manufacturer of fiber optic cables since the beginning. State of the art test equipment and highly trained professionals ensure top quality fiber optic products. Take a look at the process involved in making, testing, and the history of fiber optic cable.

For more information, visit Fiber Optic Cable

Related Fiber Posts:
Loose Tube vs Tight Buffer Fiber - What's the Difference?
10 Gigabit Ethernet Technology Overview
Glossary of Common Fiber Optic Terms
How To Make Fiber Optic Patch Cables... Kinda

Monday, June 7, 2010

What is Plenum Cable/Innerduct and When Do I Use it?

What is Plenum?

According to the National Electric Code (NEC) a plenum is a "compartment or chamber to which one or more air ducts are connected and [which] forms part of the air distribution system." To qualify as a plenum, the space above an acoustic tile ceiling would have to extend above other rooms in the same building or be open to ducts connecting it to other parts of the building. The concern is that during a fire, if there is burning material in a plenum air space, smoke and fumes can travel through air ducts to the whole building. For this reason, there are codes to restrict the types of materials (such as wiring) that can be placed in the plenum.

It's quite common to have an acoustic tile ceiling without having a plenum. If your room-dividing walls extend above the dropped ceiling and seal off the space above, you do not have a plenum air space and so may not require plenum-rated wires. You can lift up an acoustical tile in your room and peek in to see if your room has a plenum.

What is the code?

According to the National Electric Code (NEC), in plenum air spaces you must use plenum rated cables, also called Communications Plenum Cable (CMP). Plenum cable is only required when cable is installed in a plenum air space. Materials kept below the ceiling — including speaker wire, computer cables, telephone cords, etc. — do not need to be plenum rated according to the NEC.

Remember that even though the National Electric Code may allow non- plenum cable, the final decision is up to your local Fire Marshall. Most cities adopt the national codes as their own without revision, but some cities modify or expand them and require plenum-rated cable in all situations. Regardless of the code or its interpretation, your Fire Marshall makes the final decision. We recommend that you contact your Fire Marshall if you have questions.

Why is the regulation for plenum air spaces but not for inside the classroom?

It's dangerous to inhale fumes from any burning material. Communications cable is no more dangerous than any other plastic item you would find below the ceiling in a typical classroom — computers, carpet, power cords, etc. Therefore, requiring the use of plenum wires within the classroom itself would have little impact. The regulation covers the area where it's most critical.

How is plenum cable and innerduct different from CRM/PVC?

The Plenum rated coating on wire burns at a much higher temperature and emits fewer fumes.

What does plenum wire look like?

Identifying this cable just by looking at it is hard to tell. It is very similar in look and feel, so you'll want to check the print on the jacket for the letters "CMP"

Who sets the guidelines?

The National Electrical Code (NEC) is a set of guidelines recommending procedures to reduce the risk of fires, electric shock and other hazards associated with electrical installations. The code is advisory in nature, but most state and local building departments across the country use the NEC as the basis for their own electrical codes. Some local codes may be more restrictive, so please check with your local Fire Marshall if you're unsure.

Is compliance with the locally-adopted code mandatory?

Yes. City, county or state codes are mandatory and enforceable as law.

Make sure you and your contractor are on the same page. When life has been lost in a fire a lawsuit is not out of the question if plenum wire has not been installed when it should have been.

Friday, June 4, 2010

Glossary of Common Fiber Optic Terms: R - Z

Common Fiber Terms A-E

Common Fiber Terms F-L

Common Fiber Terms M-P

Common Fiber Terms: R-Z


Rack Panels
Framework or boxes to hold patch panels and other cable management devices.

Rayleigh Scattering
Scattering by refractive index fluctuations (inhomogeneities in material density or composition) that are small with respect to wavelength. Referred to as backscatter.

A device which detects an optical signal, converts into an electronic form, then processes it further so it can be used by electronic equipment. From the standpoints of components, it can be viewed as a combination of detector and single processing electronics.

Receiver I.C.
Consists of photodiode which converts the signal to an elec­tronic one which feeds into an amplifier bringing the signal back to a level.

Receiver Sensitivity (expressed in dBm)
This tells how much optical power the photo-detector must receive to achieve a specified base band per­formance, such as a specified bit-error rate of signal-to-noise ratio.

The abrupt change in direction of a light beam at an interface between two dissimilar media so that the light beam returns into the media from which it originated.

The bending of a beam of light at an interface between two dissimilar media or in a medium whose refractive index is a continuous function of position (graded index medium).

Repeater (fiber optic)
A device which detects a weak signal in a fiber optic communication system, amplifies it, cleans it up, and retransmits it in optical form. Also known as a regenerator.

Return Loss
Expressed in negative value (-dB), this refers to the amount of back reflection. The lower the dB value, the better the connector and polish finish on the connector ferrule.

RF (Radio Frequency)
The frequency spectrum from 15kHz to 100GHz.

RFI (Radio Frequency Interference)
Electromagnetic radiation in the radio frequency spectrum fiom 15kHz to 100GHz. The best shielding material against RFI is copper and aluminum alloys. The term "EMI" should not be used in place of RFI since shielding materials for the entire electromagnetic frequency spectrum are not available.

Pathways for indoor cables that pass between floors. It is normally a vertical shaft or space. Also a fire-code rating for indoor cable.


A property of glass that causes light to deflect from the fiber and contributes to optical attenuation.

Scribe Tool
Also called a cutting tool or breaking tool, consisting of cut­ting blade usually made from tungsten carbide or a diamond. Application is to break/scribe fiber @90? without lips or hackles or angular irregularities.

Selco Lenses
Segments of optical fibers specially designed to function as lenses.

Semi-Graded Index
An optical fiber with refractive index profile interme­diate between step-index and graded index. Strictly speaking, this might be considered a type of graded-index fiber with refractive index profile some­what steeper than normal.

Signal-to-Noise Ratio
The ratio of the power of the signal to that of background noise, usually measured in decibels. This is a common measure of the quality of analog electronics or transmission systems.

Simplex Cable
A single cable structure with a single fiber.

One type of low-loss optical waveguide with a very small Core (2-9 microns). It requires a laser source for input signals becauuse of the very small entrance aperture. The core diameter of a single-mode is designed to accept a one mode(wavelength) from the light source .

Skew Rate
A ray somethimes refered to as a dominant ray, that never intersects the axis of fiber while being internally reflected (in contrast with a meridional ray).

A permanent junction between two optical-fiber ends.

Splice Housing (Fiber Optics)
A housing designed to protect a splice in an optical fiber from damage by the environment, such as from the applica­tion of stress on the fiber. It also can seal the splice fiom environmental agents such as water which could cause it to deteriorate.

Star Coupler (fiber optics)
A coupler in which many fibers are brought together to a single optical element in which their signals are mixed. The mixed signals are then transmitted back through all the fibers. The name comes from the geometric arrangement

An optical fiber in which there is a discontinuous (step-function) change in refractive index at the boundary between fiber core and cladding. Such fibers have a large numerical aperture (light accepting angle), and are simple to connect. but have lower bandwidth than other types of optical fibers.

Mechanical tool used to remove buffer coatings from fibers.

Standard TTL (see TTL)

To displace metal by pressure.

Switch (fiber optics)
A device for rerouting signals from one optical fiber into others.


Tap (fiber optic)
A coupler in which part of the light carried by one fiber is split off and inserted into another fiber, essentially the same as a Tee coupler.

Tee Coupler (fiber optic)
A fiber optic coupler in which three fiber ends are joined together, and a signal transmitted from one fiber is split between the other two. A conceptual drawing looks like the letter T, which accounts for the name.

Telecommunications Closet (TC)
An enclosed space for housing telecommunications equipment, cable terminations, and cross-connects. The closet is the recognized cross-connect between the backbone and horizontal cabling.

Termination tools
Tools used in preparing optical fibers for spliciug and/or installation of connectors.

Tight Buffered Cable
a protective coating extruded tightly over fiber for mechanical and environmental protection. The coating material is either nylon or PVC. This buffering offers excellent physical and flexing properties, but higher micro-bending sensitivity.

Time-Division multiplexing
A digital technique for combining two or more signals into a single stream of data by interleaving bits from each signal. Bit one might be from signal one, bit two from signal two, etc.

Total Internal Reflection
The total reflection that occurs when light strikes an interface at angles of incidence greater than the critical angle.

Transmitter (fiber optics)
A light source (LED or diode laser) which is combined with electronic circuitry to drive it. A transmitter operates directly from the signal generated by other electronic equipment to produce the drive current needed for LED or diode laser.


Wavelength-Division Multiplexing
Combination of two or more signals so they can be transmitted over a common optical path, usually over a single fiber; by a technique in which the signals are generated by light sources having different wavelengths. For example, one signal might be transmitted at 850 nanometers and a second at 1300 nanometers.

Wave Division Multiplexing. Multiplexing is done by combining different wavelengths over one optical fiber simultaneously. Each wavelength is capable of carrying a certain amount of information.

White Light
A mixture of colors of visible light that appears white to the eye. In theory, a mixture of three colors is sufficient to product white light.


Zero-Dispersion Wavelength
Wavelength at which the chromatic dispersion of an optical fiber is zero. Occurs when waveguide dispersion cancels out material dispersion.

Glossary of Common Fiber Optic Terms: M - P

Common Fiber Terms A-E

Common Fiber Terms F-L

Common Fiber Terms: M-P


In an optical fiber, all macro deviations of the axis from a straight line.

Material Dispersion
The dispersion associated with a non-monochromatic light source due to the wavelength dependence of the refractive index of a material or of the light velocity in this material.

Mating Sleeve
A mechanical media termination device designed to align and join fiber optic connectors of the same type. Often referred to as a coupling, bulkhead, or interconnect sleeve.

Mechanical Splicing
Joining two fibers together by permanent or temporary mechanical means (vs. fusion splicing or connectors)

Megahertz (MHz)
A unit of frequency that is equal to one million cycles per second.

Meridional Ray
A ray that passes through the axis of a fiber while being internally reflected (in contrast with a skew ray) and is confined to a single plane.

Microbending Loss
In an optical fiber, loss caused by sharp curvatures involving local axial displacements of a few micrometers and spatial wavelengths of a few millimeters. Such bends may result from fiber coating, cabling, packaging, installation, etc.

A unit of length equal to one-millionth (10 E-6) of a meter (same as a micrometer).

Modal Dispersion
Pulse spreading due to multiple light rays traveling different distances and speeds through an optical fiber.

A stable condition of oscillation in a laser. A laser can operate in one mode (singlemode) or in many modes (multimode). The theoretical underpinnings are extremely complex; the main practical implications are in beam quality.

Mode Changing
In a optical fiber, the exchange of power among modes.

Mode Conditioning Patchcord
a duplex multimode cord that has a small length of singlemode fiber at the start of the transmission leg. The basic principle behind the cord is that you launch your laser into the small section of single mode fiber. The other end of the singlemode fiber is cou­pled to multimode section of the cable with the core offset from the center of the multimode fiber. The laser light thus misses the "dip" and this new launch condition more closely mimics a standard LED launch. The bonus is that you still retain the speed advantages of using a laser.

Mode Filter
A device to remove high order modes to simulate equilibrium mode distribution in a short length of optical fiber.

Mode Scrambler
A device for inducing mode coupling in an optical fiber.

Coding of information onto the carrier frequency. This includes amplitude, frequency, or phase modulation techniques.

See Singlemode

Multifiber Cable
In general usage, a fiber optic cable which containsmany fibers which transmit signals independently and are housed in separate substructures within the cable or otherwise isolated from one another. This term is usually not applied to bundles of fibers which together transmit single signal.

An optical waveguide with a relatively much larger core (commonly 50 to 62.5 micron) than the singlemode waveguide core (2 to 9 microns) and which permits approximately 1000 modes to propagate through the core compared to only one mode through a singlemode fiber.

A device which combines two or more separate signals for transmission through a single fiber. Optical multiplexers combine signals at different wavelengths. Electronic multiplexers combine signals electronically before being converted into optical form.


One-Billionth of a meter (10 E-9) (same as a millimicrometer).

Non-Silica Glasses
A glass in which the primary constituent is a material other than silica (silicon dioxide). The term is sometimes applied to mean non-oxide glasses, those which do not contain oxide compounds. In fiber optics, some of these materials are used for fibers transmitting mid-infrared wavelengths.

Numerical Aperture
NA The numerical aperture of an optical fiber defines a characteristic of the fiber in terms of it's acceptance of light. The "degree of openess", "light gathering ability" and "acceptance cone" are all terms describing this characteristic.


Optical Fiber, Non-conductive, Plenum rated.

Optical Fiber, Non-conductive, Riser rated.

OM1 Fiber Classification (FDDI)
OM1 is legacy (FDDI) grade fiber originally designed for use with LEDs and tend to be 62.5/125 types.  OFL Bandwidth (LED) 850/1300nm ( is 200 / 500.  

OM2 Fiber Classification (50/125)
OM2 fibers enable maintenance and extension to existing 50/125 cabling.  OFL Bandwidth (LED) 850/1300nm ( is 500 / 500

OM3 Fiber Classification (10Gb/s)
OM3 fibers can support 10 Gb/s over 300 meters and are recommended for all new network builds for link distances up to 300 meters. OFL Bandwidth (LED) 850/1300nm ( is 1500 / 500, and Effective Laser Launch Bandwidth at 850nm is 2000  

Optical Attenuation Meter (Attenuator)
Device which measures the loss or Attenuation of an optical fiber, fiber optic cable, or a fiber optic system. Measurements generally are made in decibels.

Optical Break
The breaking of an optical fiber in such a way which predictably produces flattened surfaces that are perpendicular to the longitudinal axis of the fiber. Sometimes referred to as a mirror-like surface across the entire end surface.

Optical Return Loss (ORL)
a reflection that travels down the fiber back to the source. In high speed systems this is undesirable because it can interfere with the transmission. Also referred to as “back reflection”.

Optical Time Domain Refectometer (OTDR)
A method for characterizing a fiber via an optical pulse transmitted through the fiber. The resulting backscatter and reflections are measured as a function of time. The OTDR is useful in measuring attenuation, in distance and identification of defects and other losses.

Output Power (LED)
Radiant power expressed in watts.


Patch Panel
Flat strip of material with adapters for interconnections. Generally 6, 8, or 12 per panel. See Rack Panels

A length of cable with connectors at both ends. Also known as jumpers.

Abbreviation used to denote polyethylene. A type of plastic material used for outside plant cable jackets.

A diode designed to produce photocurrent by absorbing light. Photodiodes are used for the detection of optical power and for the conversion of optical power into electrical power.

A short length of optical fiber with one connector on one end and no connector on the other end.

Pin Photodiode
A semiconductor diode light detector in which a region of intrinsic silicon separates the p and n materials. It offers particularly fast response and is often used in optic systems.

Plastic Clad SiIica (PCS)
A step index optical fiber in which a silica core is covered by a transparent plastic cladding of lower refractive index that of the core. The plastic cladding is usually a soft material, although hard-clad versions have recently been introduced. Offers good radiation resistance.

Plastic Fibers
Optical fibers in which both core and cladding are made of plastic material. Typically their transmission is much poorer than that of glass fibers, and their lowest losses are in the visible region.

An air-handling space such as that found above drop-ceiling tiles or in raised floors. Also, a fire code rating for indoor cable.

Polarization-Maintaining Fiber
A singlemode optical fiber which maintains the polarization of the light which entered it, normally by including some birefringence within the fiber itself. Normal singlemode fibers, and all other types, allow polarization to be scrambled in light transmitted through them.

A step in the connectorization process that creates a flat even surface on the ferrule face. Quality is measured in terms of back reflection reduction. Also referred to as “finish”

Polyethylene (PE)
A type of plastic material used for outside plant cable jackets.

Polyvinyl-chloride (PVC)
A type of plastic material used for cable jacketing. Typically used in flame-retardant cables.

Pulse Dispersion (pulse spreading)
The separation or spreading of the input characteristics of the optical signal that appears along the length of the optical fiber and limits the useful transmission bandwidth of the fiber. Expressed in time and distance a nanoseconds per kilometer. Three basic mechanisms for dispersion are the material effect, the waveguide effect, and the multimode effect.

Pulse Suppressor
A launching fiber used to take up the unmeasurable beginning (dead zone) of an OTDR.

Abbreviation used to denote polyvinyl-chloride. A type of plastic material used for cable jacketing. Typically used in flame-retardant cables.

Abbreviation used to denote polyvinyldiflouride. A type of material used for cable jacketing. Often used in plenum-rated cables.

Common Fiber Terms R-Z

Glossary of Common Fiber Optic Terms: F - L

Common Fiber Terms A-E

Common Fiber Terms: F-L


A multi-fiber cable constructed in a tight buffered tube design. At a termination point, cable fibers must be separated from the cable to their separate connection positions.

A component of fiber optic connections that holds a fiber in place and aids in it's alignment. It is the protruding portion of the connector, made of Ceramic, Stainless Steel, or Polymer, and is polished during the connection process to form a smooth finish.

Fiber Buffer
Material used to protect an optical fiber or cable from physical damage. providing mechanical isolation or protection. Fabrication techniques include both tight jacket, or loose tube buffering, as well as multiple buffer layers.

Fiber Optic Cable
A sub-assembly made up of several optical fibers incorporated into an assembly of organic materials arranged for providing the necessary tensile strength, external protection, and handling properties comparable to those of equivalent diameter coaxial cables.

Fiber Optics
The technique of conveying light or images through a particular configuration of glass or plastic fibers. Fiber optics can be categorized roughly into three groups: incoherent, coherent and specialties.

   1. Incoherent fiber optics will transmit light|like a pipe will water|but not an image.
   2. Coherent fiber optics can transmit an image through the perfectly aligned small (12 micron) clad optical fibers (image carrying).
   3. Specialty fiber optics combines some aspects of a and b.

Fiber Sensor
A sensing device in which the active sensing element is in an optical fiber or an element attached directly to an optical fiber. The quantity being measured changes the optical properties of the fiber in way that can be detected and measured. For example, pressure changes induced in a fiber by acoustics can change the amount of light transmitted by a fiber.

Field Installable (fiberoptics)
Nominally, a fiber optic splice or cable is field installable if it can be mounted by technicians working in the field without a lab-full of equipment at hand. Different manufacturers define the term differently.

Refers to the polish results on the end of the ferrule. Better the Finish, the less the back reflectance.

Frequency-Division Multiplexing
The combination of two or more signals at different frequencies so they can be transmitted as one signal. This can be done electronically, or it can be done optically by using two or more light sources of different wavelengths. The optical version is better known as wavelength division multiplexing.

Fresnel Relflection
Reflection losses that are incurred at the input and output faces of the fiber and are due to the difference in refractive index between the core glass and the immersion medium.

“Fiber to the Home" FTTH is where fiber will be brought directly to the side of your home to support your cable TV, telephone service and internet needs. It looks much like the utility box that you currently have on the side of your home, only with fiber jumpers inside.

Furcation Tubing
A protective tubing used to protect exposed fiber. Commonly used in terminating multi-fiber cable or “fan out” situations.

Fusion splicer
A high precision piece of equipment that allows the user to 'melt' or fuse the ends of two optical fibers together to create one continous fiber. There is typically very low loss at this junction. Alignment of fibers can be by manual or automatic manipulation. The fusing takes place by electrical discharge between two electrodes.


Gigahertz (GHz)
A unit of frequency that is equal to one billion cycles per second.

Graded Index Fiber
An optical fiber in which the refractive index changes gradually between the core and cladding, in a way designed to refract light so it stays in the fiber core. Such fibers have lower dispersion and hence broader bandwidth than step-index fibers.


Hard-Clad Silica Fluid
A liquid with refractive index that matches that of the core or cladding of an optical fiber. It is used in coupling light into or out of optical fibers and can help in suppressing reflections at glass surfaces.

Hybrid Cable
A fiber optic cable containing two or more different types of fiber, such as 62.5um multimode and singlemode.


Index Matching Gel
A gel material with an index of refraction close to that of glass that reduces reflections caused by refractive-index differences.

Index of refraction
The ratio of light velocity in a vacuum to its velocity in a given transmission medium.

Those wavelengths that extend beyond 770 nanometers. Infrared is used extensively in the transmission of light through optical waveguides. These light wavelengths are invisible and harmful to the naked eye.

Insertion Loss
Total optical power loss caused by insertion of an optical component such as a connector, splice, or coupler into a previously continuous path.

Interconnect Sleeve
A mechanical media termination device designed to align and join fiber optic connectors, designed to be mounted on a panel. Often referred to as a coupling, bulkhead, or mating sleeve.

Interferometer Test
A test used to determine the quality of the ferrule surface using three measurements.

   1. The angle of the cut or radius on the end of a connector which determines actual back reflection values or characteristics.
   2. The undercut or protrusion of the fiber. This is mea­sured against the ferrule end face determining how well the physical contact will be.
   3. The position of the fiber in relation to cut or curve, called the apex.

Intrinsic Joint Loss
Loss caused by fiber parameter (e.g.: core dimensions, profile parameter) mismatches when two non identical fibers are joined.


A length of cable with connectors at both ends. Also known as patchcords.


Strands of aramid yarn used to provide strain relief in cable assemblies.

Kilometer (km)
One thousand meters, or approximately 3281 feet. The kilometer is a standard unit of length measurement in fiber optics. Conversion is 1 ft. = 0.3048


A Local Area Network. A network which does not utilize outside telco company lines.

Large-Core Fiber
An optical fiber with a comparatively large core, usually a step-index type. Usually, 400 micrometers or more (see Step Index).

An acronym for Light Amplification by the Stimluated Emission of Radiation, applied to a wide range of devices which produce light by that principle. Compared other light sources, laser light covers a narrow range of wavelengths. tends to be coherent, and is emitted in a directional beam.

Launch Fiber
A fiber used in conjunction with a source to excite the modes of another fiber in a particular way. Launching fibers are most often used in test systems to improve the precision of measurements. See “Pulse Suppressor”

LED (Light-Emitting Diode)
A semiconductor device in which light is produced when current carriers combine at a p-n junction. The emission is spontaneous and there are no feedback mirrors, unlike diode lasers. Output is lower in power than from diode lasers, reflecting the use lower operating currents. Generally LEDs are less expensive than diode lasers, and can operate at shorter wavelengths without the rapid degradation that occurs with visible-wavelength diodes.

Loose Buffer Cable
Loose buffered designs Consist of a loose tube surrounding a coated fiber. It also includes a Kevlar? braid as the strength member for improved flexibility.

LSTTL (Low Power Schottky TTL)
Utilizes a diode-clamped transistor to lower power requirememts.

Common Fiber Terms M-P

Common Fiber Terms R-Z

Glossary of Common Fiber Optic Terms: A - E

Common Fiber Terms: A-E


A.T.C. (Automatic Threshold Control)
Electric control circuit which regulates the input current to an LED to prevent it from being overdriven.

Absorption Losses
Losses caused by impurities principally transition metals and neighboring elements (Cr, Mn, Fe, Co, Ni), and also by water as well as intrinsic material absorption.

Acceptance Angle
Any angle measured from the longitudinal center line up to the maximum acceptance angle of an incident ray that will be accepted by the waveguide. The maximum acceptance angle is depend­ent on the indices of refraction of the two mediums.

A mechanical media termination device designed to align and join fiber optic connectors. Often referred to as a coupling, bulkhead, or interconnect sleeve.

Angle on Incidence
The angle between an incident ray and the normal to a reflecting surface.

Aramid Yarn
Fibers, yellow, that provide cable tensile strength, support, and additional protection of the optical fiber bundles. KevlarĂ’ is a particular brand of aramid yarn. Often refered to as central strength member.

Protective material in cable made of corrugated steel.

A method of data multiplexing that can provide large, instantaneous bandwidths for busy traffic while permitting slow traffic to use that bandwidth between bursts. Very short, fixed-length packets or cells are used to transmit information. Its basic cell is 53 bytes long.

a measure of the decrease in energy transmission (loss of light) expressed in dB/Km. When in optical wave guides it is primarily due to absorption losses and scattering losses.

Avalanche photodiode (APD)
A type of semiconductor detector operated at high voltages. When incident light generates photoelectron from the material, the high voltage across the device accelerates the elec­tron enough to cause avalanche of other electrons, effectively amplifying the signal. An avalanche photodiode could be seen as similar to a solid state photo-multiplier.

Axial Ray
A ray passing through the axis of the optical waveguide without any internal reflection.


Back Reflection
An undesirable characteristic in singlemode fiber transmission. Reflectance of light pulse back towards the transmitted source. Also referred to as Optical Return Loss (ORL).

See “Back Reflection”

The capacity of an optical fiber to transmit information expressed in bits of information transmitted in a specific time period for a specific length of optical wave guide. (Usually expressed in megabits/sec./km.) Bandwidth is limited by pulse spreading or broadening due to dispersion, so that adjacent pulses overlap and cannot be distinguished. (see Pulse Dispersion)

A device which divides a beam of light passing through it into separate beams going in two different directions. Some types affect polarization of the beam, while others do not. Various splitting ratios are possible. (eg., 90-10, 70-30, 50-50, etc.)

Bend Radius
Maximum bend allowed before physical damage is incurred. Generally expressed for two conditions, loaded (under tensile load) or unloaded.

An electrical light pulse whose presence or absence indicates data. The capacity of the optical waveguide to transmit information through the waveguide without error is expressed in bits per second per unit length.

Bragg Gratings, Fiber
Fiber that is treated to back reflect a particular wavelength, called the Bragg Wavelenth. See technical notes: Fiber Bragg Gratings

Material used to protect an optical fiber or cable from physical damage and providing mechanical isolation or protection. Fabrication techniques include both tight jacket, or loose tube buffering, as well as multiple buffer layers.

Bulkhead Attenuator
A mechanical media termination device designed to align and join fiber optic connectors, designed to be mounted on a panel, and that contains an attenuation device.

Bulkhead Connector
A mechanical media termination device designed to align and join fiber optic connectors, designed to be mounted on a panel. Often referred to as a coupling, bulkhead, interconnect or mating sleeve.


Card-Edge Connector
Designed for printed circuit boards for blind mating of connectors.

Central Member
The center component of a cable used to provide strength. Commonly referred to as “Central Strength Member”

Chromatic Dispersion
Spreading of a light pulse caused by the difference in refractive indices at different wavelengths.

A low refractive index, glass or plastic that surrounds the core of a fiber. Optical cladding promotes total internal reflection for the propagation of light in a fiber.

A process in which a divergent or convergent beam of radiation is converted into a beam with the minimum divergence as possible, preferably parallel.

Composite Cable
A cable containing both fiber and copper conductors.

A junction which allows users to connect / disconnect cables or devices.

The light conducting portion of a fiber, defined by its high refraction index. The core is the center of a fiber, surrounded by concen­tric cladding of lower refractive index.

Core Eccentricity
A measure of the displacement of the center of the core relative to the cladding center.

Core Ellipticity (non-circularity
A measure of the departure of the core from roundness.

Coupler (fiber optic)
A coupler is a device which joins together three or more fiber ends, for example, splitting the signal from one fiber so it can be transmitted to two or more other fibers. Directional , star, and tee couplers are the most common varieties.

Coupling Loss
The power loss suffered when coupling light from one optical device to another.


Dark Current
The output current that a photodiode emits in the absence of light.

Data Link (fiber optic)
A fiber optic signal transmission system which carries information in digital or (sometimes) analog form. Usually this term refers to short-distance communications, spanning distances of less than a kilometer.

Data Rate
The maximum number of bits of information that can be transmitted per second, as in a data transmission link. Typically expressed as megabits per second (Mbps)

Decibels relative to one milliwatt. A positive number indicates the power is above one milliwatt; a negative number indicates the power is below. This unit has become common in fiber optic communication sys­tems because the power of light sources used with optical fibers is on the order of one milliwatt.

The standard unit used to express the ratio of two power 1evels. It is used in communications to express either a gain or loss in power between the input and output devices.

A device which separates two or more signals that have been multiplexed together for transmission through a single fiber. (See multiplexer.)

A transducer that provides an electrical output signal in response to an incident optical signal. The current is dependent on the amount of light received and the type of device.

A device in which an optical detector is packaged together with electronic amplification circuitry.

Non-metallic, and therefore, non-conductive. Glass fibers are considered dielectric. A dielectric cable contains no metallic components.

Diode Adapter Receptacle
Designed to house LED or PlN/APD diodes in a receptacle which allows the mating plug to position the fiber for an optimum coupling efficiency.

Directional Coupler (fiber optics)
A fiber coupler is directional if it preferentially transmits light in one direction.

Spread of the signal delay in an optical waveguide. It consists of various components: modal dispersion, material dispersion, and waveguide dispersion. As a result of its dispersion, an optical waveguide acts as a low-pass filter for the transmitted signals.

The spreading out of a laser beam with Distance, measured as an angle.

Doppler Shift
A change in the wavelength of light caused by the motion of an object emitting (or reflecting) the light. Motion toward the observer causes a shift toward shorter wavelengths, while motion away causes a shift toward longer wavelegths.

Driver I.C
An amplifier in an integrated circuit used to increase signal current to the LED for greater transmission distance.

Duplex Cable (fiber optics)
A cable which contains two optical fibers in a single cable structure. Light is not coupled between the two fibers: typically one is used to transmit signals in one direction and the other used to transmit in the opposite direction.

Duplex Connector (Fiber optics)
A connector which simultaneously makes two connections, joining one pair of optical fibers with another.


E.C.L. (Emitted-Coupled Logic)
Method of data transmission which uses negative logic. -0.8V is "1" and -1.6V is "0".

Electromagnetic Interference (EMI)
The frequency spectrum of electromagnetic radiation extending from subsonic frequency to X-rays. This term should not be used instead of the term "RFI" (see RFI) (Shielding materials for the entire EMI spectrum are not readily available.)

EMP (Electromagnetic Pulse)
An extremely strong short lived magnetic field resulting from a nuclear explosion could cause a damaging magnetic field at a distance of 1500-3000 miles.

End Finish
Quality of the surface of an optical fiber's end, commonly described as mirror, mist, hackle, chipped, cracked or specified by final grit size in polishing. (1um, .3um, etc.). See “Polish”

End Separation Loss
The optical power loss of a fiber and source, detector or another fiber (see Frensel Reflection).

Extinction ratio
a performance standard measurement of polarization maintaining (PM) fiber. The measurement of light entering and exiting a fiber indicates how well the fiber maintains polarization.

Extrinsic joint Loss
Loss caused by imperfect alignment of fibers in a connector or splice. Contributors include angular misalignment, lateral offset, end separation and end finish. Generally synonymous with Insertion loss.

Common Fiber Terms F-L

Common Fiber Terms M-P

Common Fiber Terms R-Z

Wednesday, May 19, 2010

How To View Security System DVR with Your Cell Phone - iPhone - Blackberry

In today's economy, theft is a rising concern for homeowners/business owners. According to the Federal Bureau of Investigation, there were an estimated 6.6 million (6,588,873) larceny-thefts nationwide in 2008. The loss to victims was nearly $6.1 billion. That's a $925 loss on average. Newer technology is helping us pave the way for a safer future, and cell phone's have played a crucial role. With advancements in DVR technology, it is now possible to view your security system remotely. Everfocus has introduced 2 new DVRs that support mobile viewing, the Paragon264 and ECOR264 series. Here's how you set up your DVR for mobile viewing:

1) The DVR must be accessible from the internet via the same process usually employed for DVR remote viewing:
     a. the DVR IP configuration must be consistent with the local network
     b. the router in the system must be configured to forward any traffic for the HTTP port used by the DVR to the IP address of the DVR. Please refer to the DVR User Guide for setting up the DVR network configuration.
2) In the Configuration Menu Network Setting Screen, the new option in the LAN setup "Enable Mobile Viewing" must be checked.

To view, launch the web browser on the mobile device or PC and enter the URL in the form:


where ZZZ.ZZZ.ZZZ.ZZZ is the IP address of the DVR
PPPP is the HTTP port used by the DVR
dvrddnsname is the DDNS name registered with the server

You will be prompted for the login ID and password to access the DVR. Please remember that the ID is case sensitive and the password is numeric.

After entering the ID/Password, choose "OK" or "Log In" and you will see the live view screen. Click on a camera button to select that camera.

Everfocus H.264 DVR's are compatible with many different types of cell phones for remote viewing

Current Mobile Device Verified Compatibility *** (updated 8/3/10) ***

Apple iPhone on Safari
Apple iPhoneGS on Safari
Apple iPod Touch on Safari

T-Mobile/HTC Wing on Opera 10/Windows Mobil
T-Mobile/HTC MDA on Opera 10/Windows Mobil
T-Mobile/HTC HD2 on Opera 10/Windows Mobil
T-Mobile/HTC myTouch on Opera 10/Windows Mobil
T-Mobile/Google G1 on Included Browser

Motorola Droid on Included Browser
Motorola Droid X on Included Browser

Blackberry Bold on Included Browser
Blackberry Curve on Included Browser
Blackberry Tour on Included Browser
Blackberry 8220 on Included Browser
Blackberry 8300 on Included Browser
Blackberry 9000 on Included Browser

Samsung Jack on Opera Mobile 10/Windows Mobile 6.5

(Note: This may not be the complete list. This is just the ones we have verified that will work. If you have an older model DVR, you might be required to Upgrade Your Firmware for cell phone viewing on certain models.)

Related Posts:
Press Release - H.264 Compression Technology
Security Camera System Frames Per Second Comparison Video
How To Create a Low Budget CCTV System
Ideal SecuriTest Pro CCTV Camera Tester

Friday, May 7, 2010

10 Gigabit Ethernet Fiber Optic Technology Overview

10 Gigabit Ethernet Technology Overview

Executive Summary
From its origin more than 25 years ago, Ethernet has evolved to meet the increasing demands of packet-based networks. Due to its proven low implementation cost, reliability, and relative simplicity of installation and maintenance, Ethernet’s popularity has grown to the point that nearly all traffic on the Internet originates or terminates with an Ethernet connection. Further, as the demand for ever-faster network speeds has increased, Ethernet has been adapted to handle these higher speeds, as well as the surges in volume demand that accompany them. The IEEE 802.3ae* 2002 (10 Gigabit Ethernet standard) is different in some respects from earlier Ethernet standards in that it will only function over optical fiber, and only operates in fullduplex mode (collision-detection protocols are unnecessary). Ethernet can now progress to 10 gigabits per second while retaining its critical Ethernet properties, such as the packet format, and the current capabilities are easily transferable to the new standard.

The 10 Gigabit Ethernet Standard
The 10 Gigabit Ethernet standard extends the IEEE 802.3ae* standard protocols to a wire speed of 10 Gbps and expands the Ethernet application space to include WAN-compatible links. The 10 Gigabit Ethernet standard provides a significant increase in bandwidth while maintaining maximum compatibility with the installed base of 802.3 standard interfaces, protects previous investment in research and development, and retains the existing principles of network operation and management.

Under the Open Systems Interconnection (OSI) model, Ethernet is fundamentally a Layer 1 and 2 protocol. 10 Gigabit Ethernet retains key Ethernet architecture, including the Media Access Control (MAC) protocol, the Ethernet frame format, and the minimum and maximum frame size. Just as Gigabit Ethernet, both 1000BASE-X and 1000BASE-T, followed the standard Ethernet model, 10 Gigabit Ethernet continues the evolution of Ethernet in speed and distance, while retaining the same Ethernet architecture used in other Ethernet specifications, except for one key ingredient. Since 10 Gigabit Ethernet is a full-duplex only technology, it does not need the carrier-sensing multiple-access with collision detection (CSMA/CD) protocol used in other Ethernet technologies. In every other respect, 10 Gigabit Ethernet matches the original Ethernet model. At the physical layer (Layer 1), an Ethernet physical layer device (PHY) connects the optical or copper media to the MAC layer through a connectivity technology (Figure 1). Ethernet architecture further divides the physical layer into three sublayers: Physical Medium Dependent (PMD), Physical Medium Attachment (PMA), and Physical Coding Sublayer (PCS). PMDs provide the physical connection and signaling to the medium; optical transceivers, for example, are PMDs. The PCS consists of coding (e.g., 64B/66B) and a serializer or multiplexor. The IEEE 802.3ae* standard defines two PHY types: the LAN PHY and the WAN PHY. They provide the same functionality, except the WAN PHY has an extended feature set in the PCS that enables connectivity with SONET STS-192c/SHD VC-4-64c networks.

10 Gigabit Ethernet in the Marketplace
Ethernet technology is currently the most deployed technology for high-performance LAN environments. Enterprises around the world have invested cabling, equipment, processes, and training in Ethernet. In addition, the ubiquity of Ethernet keeps its costs low, and with each deployment of next-generation Ethernet technology, deployment costs have trended downward. In networks today, the increase in worldwide network traffic is driving service providers, enterprise network managers and architects to look to faster network technologies to solve increased bandwidth demands. 10 Gigabit Ethernet has ten times the performance over Gigabit Ethernet today. With the addition of 10 Gigabit Ethernet to the Ethernet technology family, a LAN now can reach further distances and support even more bandwidth hungry applications. 10 Gigabit Ethernet also meets several criteria for efficient and effective high-speed network performance, which makes it a natural choice for expanding, extending, and upgrading existing Ethernet networks: A customer’s existing Ethernet infrastructure is easily interoperable with 10 Gigabit Ethernet. The new technology provides lower cost of ownership including both acquisition and support costs versus current alternative technologies. Using processes, protocols, and management tools already deployed in the management infrastructure, 10 Gigabit Ethernet draws on familiar management tools and a common skills base. Flexibility in network design with server, switch, and router connections. Multiple vendor sourcing of standards-based products provides proven interoperability. As 10 Gigabit Ethernet enters the market and equipment vendors deliver 10 Gigabit Ethernet network devices, the next step for enterprise and service provider networks is the combination of multi-gigabit bandwidth with intelligent services, which leads to scaled, intelligent, multi-gigabit networks with backbone and server connections ranging up to 10 Gbps. Convergence of voice and data networks running over Ethernet becomes a very real option. And, as TCP/IP incorporates enhanced services and features, such as packetized voice and video, the underlying Ethernet can also carry these services without modification. The 10 Gigabit Ethernet standard not only increases the speed of Ethernet to 10 Gbps, but also extends its interconnectivity and its operating distance up to 40 km. Like Gigabit Ethernet, the 10 Gigabit Ethernet standard (IEEE 802.3ae*) supports both singlemode and multimode fiber mediums. However, in 10 Gigabit, the distance for single-mode (SM) fiber has expanded from 5 km in Gigabit Ethernet to 40 km in 10 Gigabit Ethernet. The advantage of reaching new distances gives companies who manage their own LAN environments the option to extend their data center to a more cost-effective location up to 40 km away from their campuses. This also allows them to support multiple campus locations within the 40 km distance. As we have seen with previous versions of Ethernet, the cost for 10 Gbps communications has the potential to drop significantly with the development of 10 Gigabit Ethernet-based technologies. Compared to 10 Gbps telecommunications lasers, the 10 Gigabit Ethernet technology, as defined in the IEEE 802.3ae*, will be capable of using lower cost, non-cooled optics, and vertical cavity surface emitting lasers (VCSEL), which can lower PMD device costs. In addition, an aggressive merchant chip market that provides highly integrated silicon solutions supports the industry.

Applications for 10 Gigabit Ethernet
Vendors and users generally agree that Ethernet is inexpensive, well understood, widely deployed and backwards compatible in today’s LAN networks. Today, a packet can leave a server on a short-haul optic Gigabit Ethernet port, move cross-country via a DWDM (dense-wave division multiplexing) network, and find its way down to a PC attached to a Gigabit copper port, all without any re-framing or protocol conversion. Ethernet is literally everywhere, and 10 Gigabit Ethernet maintains this seamless migration in functionality for any application in which Ethernet can be applied.

10 Gigabit Ethernet as a Fabric Interconnect
Fabric interconnects, whether they are for server area networks or storage area networks, have traditionally been the domain of dedicated, often proprietary, networks with relatively small user bases when compared to Ethernet. These server area networks include InfiniBand*, Servernet*, Myranet*, Wulfkit* and Quadrics* technologies, and offer excellent bandwidth and latency performance for very short-haul (generally less than 20 m) networks. However, with the exception of InfiniBand, these are proprietary networks that can be difficult to deploy and maintain due to the small number of experienced IT professionals familiar with the technology. The small volumes also result in higher costs for server adapters and switches. And, as with any proprietary solution, they are not interoperable with other technologies without the appropriate routers and switches.

In storage area networks, the lack of standards and a slew of interoperability problems plagued the early Fibre Channel deployments. However, these technologies also suffer similar problems as those seen by proprietary server area networks in that they are considered difficult to deploy due to lack of a skilled IT pool, are relatively expensive at the adapter and switch port, are still not directly interoperable with other network technologies without expensive routers or switching devices, and generally focus on short-haul deployments. 10 Gigabit Ethernet is in a position to replace these proprietary technologies as a next-generation interconnect for both server and storage-area networks for several reasons: 10 Gigabit Ethernet Offers the Necessary Bandwidth. In fact, InfiniBand and Fibre Channel will also begin mass deployments of 10 Gigabit technologies, indicating a convergence on 10 Gigabit throughput.

Cost-Saving Server Consolidation. 10 Gigabit Ethernet grants a single server the bandwidth needed to replace several servers that were doing different jobs. Centralization of management is also a major benefit of server consolidation. With a single powerful server, IT managers can monitor, manage, and tune servers and application resources from a single console, which saves time and maximizes IT resources. According to IDC, companies realize a seven-to-one savings in management when processes and servers are consolidated.† † IDC, Worldwide Server Consolidation Forecast, September 2002 Planned Growth of 10 Gigabit Network Features. For the first time ever, Ethernet can be a low-latency network due to RDMA (Remote Direct Memory Access) support, which is critical in the server-to-server communication typically associated with clustering and server area networks. In addition, the expected universal deployment of TOE (TCP/IP Offload Engine) technology in 10 Gigabit Ethernet adapters may make it extremely efficient on host systems with expected CPU utilization well below anything seen on today’s systems deploying Gigabit Ethernet. Due to the wide adoption rate of Ethernet, TOE technology will become extremely cost efficient compared to the lower volume, niche alternatives.

10 Gigabit Ethernet in Local Area Networks
Ethernet technology is already the most deployed technology for high-performance LAN environments. With the extension of 10 Gigabit Ethernet into the family of Ethernet technologies, LANs can provide better support the rising number of bandwidthhungry applications and reach greater distances. Similar to Gigabit Ethernet technology, the 10 Gigabit standard supports both single-mode and multimode fiber media. With links up to 40 km, 10 Gigabit Ethernet allows companies that manage their own LAN environments the ability to strategically choose the location of their data center and server farms – up to 40 km away from their campuses. This enables them to support multiple campus locations within that 40 km range (Figure 2). Within data centers, switch-to-switch

Figure 2: 10 Gigabit Ethernet use in expanded LAN environments.

Figure 3: Example of 10 Gigabit Ethernet use in a MAN.

applications, as well as switch-to-server applications, can be deployed over a more cost-effective, short-haul, multi-mode fiber medium to create 10 Gigabit Ethernet backbones that support the continuous growth of bandwidth-hungry applications. With 10 Gigabit backbones, companies can easily support Gigabit Ethernet connectivity in workstations and desktops with reduced network congestion, enabling greater implementation of bandwidth-intensive applications, such as streaming video, medical imaging, centralized applications, and high-end graphics. 10 Gigabit Ethernet also improves network latency, due to the speed of the link and over-provisioning bandwidth, to compensate for the bursty nature of data in enterprise applications. The bandwidth that 10 Gigabit backbones provide also enables the next generation of network applications. It can help make telemedicine, telecommuting, distance learning and interactive, digital videoconferencing everyday realities instead of remote future possibilities. And the fun stuff too, like HDTV, videoon-demand, or extreme Internet gaming. 10 Gigabit Ethernet enables enterprises to reduce network congestion, increase use of bandwidth-intensive applications, and make more strategic decisions about the location of their key networking assets by extending their LAN up to 40 km.

10 Gigabit Ethernet in Metropolitan and Storage Applications
Gigabit Ethernet is already being deployed as a backbone technology for dark fiber metropolitan networks. With appropriate 10 Gigabit Ethernet interfaces, optical transceivers and singlemode fiber, network and Internet service providers will be able to build links reaching 40 km or more (Figure 3), encircling metropolitan areas with city-wide networks. 10 Gigabit Ethernet now enables cost-effective, high-speed infrastructure for both network attached storage (NAS) and storage area networks (SAN). Prior to the introduction of 10 Gigabit Ethernet, some industry observers maintained that Ethernet lacked sufficient horsepower to get the job done. 10 Gigabit Ethernet can now offer equivalent or superior data carrying capacity at latencies similar to many other storage networking technologies, including Fiber Channel, Ultra160 or 320 SCSI, ATM OC-3, OC-12, and OC-192, and HIPPI (High-Performance Parallel Interface). Gigabit Ethernet storage servers, tape libraries, and compute servers are already available; 10 Gigabit Ethernet end-point devices will soon appear on the market as well.

There are numerous applications for Gigabit Ethernet today, such as back-up and database mining. Some of the applications that will take advantage of 10 Gigabit Ethernet are:
- Business continuance/disaster recovery
- Remote back-up
- Storage on demand
- Streaming media

10 Gigabit Ethernet in Wide Area Networks
10 Gigabit Ethernet enables ISPs and NSPs to create very high speed links at a very low cost from co-located, carrier-class switches and routers to the optical equipment directly attached to the SONET/SDH cloud. 10 Gigabit Ethernet, with the WAN PHY, also allows the construction of WANs that connect geographically
dispersed LANs between campuses or points of presence (POPs) over existing SONET/SDH/TDM networks. 10 Gigabit Ethernet links between a service provider’s switch and a DWDM device or LTE (line termination equipment) might in fact be very short – less than 300 meters.

Using Fiber in 10 Gigabit Ethernet
The Physical-Media-Dependent Devices (PMDs) The IEEE 802.3ae* standard provides a physical layer that
supports specific link distances for fiber-optic media. To meet the distance objectives, four PMDs (physical-media-dependent devices) were selected (Table A). The task force selected:
- A 1310 nanometer serial PMD to support single-mode fiber a maximum distance of 10 km
- A 1550 nanometer serial PMD to support single-mode fiber a maximum distance of 40 km
- An 850 nanometer serial PMD to support multimode fiber a maximum distance of 300 meters
- A 1310 nanometer wide-wave division multiplexing (WWDM) PMD to support a maximum distance of 10 km on single-mode fiber, as well as a maximum distance of 300 meters on multimode fiber

Table A: PMDs that have been selected to meet the 803.2ae* standard’s distance objectives.

Table B: The multimode optical fiber options, as defined in the IEEE 802.3ae* standard.

There are two types of optical fiber, multimode and singlemode fiber, that are currently used in data networking and telecommunications applications. The 10 Gigabit Ethernet technology, as defined in the IEEE 802.3ae* standard, supports both optical fiber types. However, the distances supported vary based on the type of fiber and wavelength (nm) is implemented in the application. In single-mode fiber applications, the IEEE 802.3ae standard supports 10 km with 1310 nm optical transmissions and 40 km with 1550 nm optical transmissions.
With multimode optical fiber, the distances are not as easily defined due to the variety of fiber types and the way each type is defined. Multimode fiber is commonly defined by the core and cladding diameters. For example, fiber with a core of 62.5 microns and a cladding diameter of 125 microns is referred to as 62.5/125micron fiber. The acceptance of multimode fiber in networks today dates back to the inclusion of 62.5/125 micron fiber into the Fiber Distribution Data Interface (FDDI) standard in the 1980s. The other portion that influences distance capabilities in multimode fiber is the fiber information carrying capacity (measured in MHz-km), which determines the distance and bit rate at which a system can operate (i.e., 1 Gbps or 10 Gbps). The distance a signal can run greatly decreases as transmission speed increases (Table B). When implementing multimode fiber for 10 Gigabit Ethernet applications, understanding the distance capabilities is a critical piece to the 10 Gigabit Ethernet solutions.

The Future of 10 Gigabit Ethernet:
Will There be Copper?
IEEE 802.3* has recently formed two new study groups to investigate 10 Gigabit Ethernet over copper cabling. The 10GBASE-CX4 study group is developing a standard for transmitting and receiving XAUI signals via a 4-pair twinax cable, commonly referred to as a 4x InfiniBand cable. The goal of the study group is to provide a standard for a low-cost inter-rack and rack-to-rack solution. It is expected to take about one year to develop a standard. The 10GBASE-T study group is developing a standard for the transmission and reception of 10 Gigabit Ethernet via a Category 5 or better unshielded twisted pair (UTP) copper cable up to 100 m. This effort is expected to take much longer than the 10GBASE-CX4 effort and current estimates are that the effort will complete sometime in late 2005 or early 2006.

Ethernet has withstood the test of time to become the most widely adopted networking technology in the world. With the rising dependency on networks and the increasing number of bandwidth-intensive applications, service providers seek higher capacity networking solutions that simplify and reduce the total cost of network connectivity, thus permitting profitable service differentiation, while maintaining very high levels of reliability. The
10 Gigabit Ethernet IEEE 802.3ae* 10 Gigabit Ethernet standard is proving to be a solid solution to network challenges. 10 Gigabit Ethernet is the natural evolution of the well-established IEEE 802.3* standard in speed and distance. In addition to increasing the line speed for enterprise networks, it extends Ethernet’s proven value set and economics to metropolitan and wide area networks by providing
- Potentially lowest total cost-of-ownership (infrastructure/operational/human capital)
- Straight-forward migration to higher performance levels
- Proven multi-vendor and installed-base interoperability (Plug and Play)
- Familiar network management feature set

An Ethernet-optimized infrastructure is taking place in the metropolitan area and many metropolitan areas are currently the focus of intense network development intending to deliver optical Ethernet services. 10 Gigabit Ethernet is on the roadmap of most switch, router and metropolitan optical system vendors to enable:

- Cost-effective, Gigabit-level connections between customer access gear and service provider POPs in native Ethernet format.
- Simple, high-speed, low-cost access to the metropolitan optical infrastructure.
- Metropolitan-based campus interconnection over dark fiber, targeting distances of 10 to 40 km.
- End-to-end optical networks with common management systems.

802.3ae – The IEEE standard for 10 Gigabit Ethernet
802.3ab – The IEEE standard for UTP Gigabit Ethernet (1000BASE-T)
802.3z – The IEEE standard for Gigabit Ethernet (1000BASE-X)
CoS – Class of Service
CWDM – Coarse-Wavelength Division Multiplexing
DWDM – Dense-Wavelength Division Multiplexing
Gbps – Gigabits per second or billion bits per second
IEEE – Institute of Electrical and Electronics Engineers
IP – Internet Protocol
ISO – International Standards Organization
LAN – Local Area Network
MAC – Media Access Control
MAN – Metropolitan Area Network
Mbps – Megabits per second or million bits per second
MMF – Multimode Fiber
OC–X – Optical Carrier Level
PCS – Physical Coding Sublayer
PHY – Physical layer device
PMA – Physical Medium Attachment
PMD – Physical Medium Dependent
POP – Points of Presence
QoS – Quality of Service
RMON – Remote Monitoring
SDH – Synchronous Digital Hierarchy
SMF – Single-mode Fiber
SNMP – Simple Network Management Protocol
SONET – Synchronous Optical Network
Tbps – Terabits per second or trillion bits per second
TCP/IP – Transmission Control Protocol/Internet Protocol
TDM – Time Division Multiplexing
WAN – Wide Area Network
WDM – Wavelength Division Multiplexing
WIS – WAN Interface Sublayer
WWDM – Wide-Wavelength Division Multiplexing

Cladding – The material surrounding the core of an optical fiber. The cladding has a lower refractive index (faster speed) that is used to keep the light in the core. The cladding and core make up an optical waveguide.
Core – The central region of an optical fiber through which light is transmitted. It has a higher refractive index (slower speed) than the surrounding cladding.
Dense-Wave Division Multiplexing – Wavelengths are closely spaced, allowing more channels to be sent through one fiber. Currently, systems using 100 GHz spacing are deployed in the WAN environment. Overall wavelength range is typically between 1530 nm to 1560 nm. The minimum and maximum wavelengths are restricted by the wavelength dependent gain profile of optical amplifiers.
Media Access Control – The media access control sublayer provides a logical connection between the MAC clients of itself and its peer station. Its main responsibility is to initialize, control, and manage the connection with the peer station. The MAC layer of the 10 Gigabit protocol uses the same Ethernet address and frame formats as other speeds, and will operate in full-duplex mode. It will support a data rate of 10 Gbps using a pacing mechanism for rate adaptation when connected to a WAN-friendly PHY.
OC-192 – A speed of SONET interconnect with a payload rate of 9.584640 Gbps, primarily used in WAN environments.
Physical Coding Sublayer – Part of the PHY, the PCS sublayer is responsible for encoding the data stream from the MAC layer for transmission by the PHY layer and decoding the data stream received from the PHY layer for the MAC layer.
PHY – The physical layer device, a circuit block that includes a PMD (physical media dependent), a PMA (physical media attachment), and a PCS (physical coding sublayer).
PMD – Part of the PHY, the physical-media-dependent sublayer is responsible for signal transmission. The typical PMD functionality includes amplifier, modulation, and wave shaping. Different PMD devices may support different media.
WWDM – A technique used to effectively transmit several wavelengths (i.e., colors of light) from several laser sources through one fiber. Each laser source would be calibrated to send a unique optical wavelength (which are separated at the receiving end of the fiber).

Appendix A – Standards Activities
The Institute of Electrical and Electronics Engineers (IEEE) was founded to foster the development of standards in all fields of science and technology within the organization’s scope. A key principle throughout the standards process is consensus among the participants. The IEEE-SA (Standards Association) and its Standards Board oversee the process of standards formation through two committees. The New Standards Committee (NesCom) ensures that proposed standards fall within the IEEE’s scope, that they are assigned to the correct technical committees, and that the makeup of working groups, etc., fairly represents all interested parties. It also
examines Project Authorization Requests (PAR) and recommends to the IEEE-SA Standards Board whether to approve them. The second committee, the Standards Review Committee (RevCom), examines proposed new and revised standards, ensures that such proposals represent a consensus among the IEEE Sponsor balloting group members, and recommends standards to the Standards Board.

For further information on the IEEE standards process or the 10 Gigabit Ethernet technology, visit the following Web sites:
IEEE 802 LAN/MAN Standards Committee
IEEE P802.3ae 10Gb/s Ethernet Task Force
10 Gigabit Ethernet Alliance (10GEA)

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