แสดงบทความที่มีป้ายกำกับ Understanding แสดงบทความทั้งหมด
แสดงบทความที่มีป้ายกำกับ Understanding แสดงบทความทั้งหมด

วันพุธที่ 25 กรกฎาคม พ.ศ. 2555

What are OFNP, OFNR, OFNG and OFCG? Understanding Fiber Optic Cable Fire Ratings

Just like copper cables, NEC (National Electrical Code) requires indoor fiber optic cables be marked with their fire and smoking ratings. NEC requires all indoor fiber cables be marked correctly and installed properly for its intended use.

According to NEC, a building's inside area is divided into three types of sections: plenums, risers and general purpose areas.

HDMI Cable

:: What is a Plenum area?

A Plenum area is a building space used for air flow or air distribution system. In most buildings, the area above a drop ceiling or under a raised floor is used as the air return (source of air) for the air conditioning. Those drop ceiling and raised floors are also where fiber cables are often installed. If those cables were burning, they would give off toxic fumes and the fumes would be fed to the rest of the building by the air conditioner. As a result, people could be injured even though they are a long way from the fire.

:: What is a Riser area?

A Riser area is a floor opening, shaft or duct that runs vertically through one or more floors

:: What is General Purpose area?

All other area that is not plenum or riser and on the same floor is a general purpose area.

:: Fiber Optic Cable Fire and Smoking Rating Markings

OFNP Cables:

OFNP stands for Optical Fiber Nonconductive Plenum. OFNP cables have fire-resistance and low smoke production characteristics. They can be installed in ducts, plenums and other spaces used for building airflow. This is the highest fire rating fiber cable and no other cable types can be used as substitutes.

OFCP Cables:

OFCP stands for Optical Fiber Conductive Plenum. OFCP cables have the same fire and smoking rating as OFNP cables but they have a conducting armor or central strength member which is usually steel. OFCP cables must be properly grounded at both ends. As a result, OFCP cables can not be installed in the same cable tray or conduit as power cables.

OFNR Cables:

OFNR stands for Optical Fiber Nonconductive Riser. OFNR cables are used in Riser areas which are building vertical shafts or runs from one floor to another floor. OFNR cables can not be installed in plenum areas since they do not have the required fire and smoking rating as Plenum rated cables. OFNP plenum cables can be used as substitutes for OFNR cables.

OFCR Cables:

OFCR stands for Optical Fiber Conductive Riser. OFCR cables have the same fire rating characteristics as OFNR cables but they have conducting armor or central strength member which is usually steel. OFCR cables should also be properly grounded at both ends. OFCP cables can be used as substitutes for OFCR cables. OFCR cables can not be installed in the same cable trays or conduits as power cables.

OFNG Cables:

OFNG stands for Optical Fiber Nonconductive General-Purpose. They are typically used in horizontal cabling, single floor applications. OFNG cables can not be used in plenums or risers. OFNP and OFNR cables both can be used as substitutes for OFNG cables.

OFCG Cables:

OFCG stands for Optical Fiber Conductive General-Purpose. They have the same fire characteristics as OFNG cables but they have conducting armor or central strength members which is typically steel. OFCG cables should be properly grounded at both ends. They should not be installed in the same cable tray or conduits as power cables.

What are OFNP, OFNR, OFNG and OFCG? Understanding Fiber Optic Cable Fire Ratings

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วันศุกร์ที่ 16 กันยายน พ.ศ. 2554

Understanding the standard DVI - DVI Explained

Digital Video Interface, or DVI cables are used to provide faster, exceptional quality, much better than their analog counterparts. This is why the DVI cables are always popular with video card manufacturers, and is offered on most graphics cards these reasons, both VGA and DVI ports. DVI is the only widespread video standard that includes an alternative analog and digital transmission in the same port.

A digital protocol used byDVI interface, which provides a desired illumination of pixels which are then transmitted as binary data. Once the display is forced to its native resolution, which will interpret each number and use the appropriate brightness for the pixels. With this method, each pixel in the output buffer of the appropriate source device directly to one pixel on the display device, although it may be affected by its adjacent pixels with an analog signal is also the manifestation of each pixelas electrical noise and other types of analog distortion.

HDMI Cable

Besides being a standard computer interface using the DVI standard has also been partially inserted into the plasma, HDTV, DVDs, films, etc. Over a number of DVD players include high-end models also have a DVI output, In addition to good Analog component video quality. There are four types of DVI connections are available, ie. DVI-Digital and DVI-Analog, DVI-Integrated (Digital and Analog) and M1-DA (digital, analogAnd USB). DVI (digital) direct connections between the graphics cards and LCD monitors. While DVI cable (analog) transmit a DVI signal to analog display in CRT and LCD older. But we must not forget that there is no loss of quality when converting from analog to digital to be, this is why we recommend a digital signal at this point.

DVI cable (integrated) are in a position to transfer the digital signal to analog or analog. This helps the DVI cable isused in either a digital or analog situations. This ensures similar to any other format, DVI (digital) and analog can not be reversed. For example, a (digital), DVI to an analog system, and vice versa. If you want to connect an analog source into digital, you need to buy a VGA to DVI-D electronic converter, just a digital output to connect an analog monitor, there is an obligation of the DVI cable (digital) are to VGA converter.

PurchaseSuggestions for the DVI cable [http://www.comnauts.com/collections/dvi-cables]:
• First, decide what type of DVI cable to get to know your products, please check the DVI female to determine their compatibility.
• Remember that if one or both connections are DVI-D, DVI-D is required if both cables are DVI-A, then a DVI-will be required.
• If the isolated compound refers to the DVI and the other belongs to VGA, DVI and an analog-compatible, youneed a DVI to VGA.
• When both compounds refers to DVI-I, you are free to use one of the DVI cables are available, but DVI-I cables are more suitable.

Understanding the standard DVI - DVI Explained

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