How to Test Fiber Optic Cables by OTDR

OTDR, full name of which is optical time-domain reflectometer is one of the most popular method of testing the light loss in the cable plant. In most circumstance, it also indicate an fiber optic testing instrument to characterized the optical fibers. OTDRs are always used on OSP cables to verify splicing loss or locating damages to the fiber optic cables. Due to the decline in the OTDR price over recent years, it is more and more applied by technicians for the system installation process.

OTDR testing

OTDR uses backscattered light of the fiber to imply loss, which is an indirect measurement of the fiber. OTDR works by sending a high power laser light source pulse down the fiber and looking for return signals from backscattered light in the fiber itself or reflected light from connectors or splice interface. OTDR testing requires a launch cable for the instrument to settle down after reflections from the high powered test pulse overloads the instrument. OTDRs can either use one launch cable or a launch cable with a receive cable, the tester result of each is also different.

Test With Launch Cable Only
A long lauch cable allows the OTDR to settle down after the initial pulse and provides a reference cable for testing the first connector on the cable. When testing with an OTDR using only the launch cable, the trace will show the launch cable, the connection to the cable under test with a peak from the reflectance from the connection, the under testing cable and likely a reflection from the far end if it is terminated or cleaved. Most terminations will show reflectance that helps identify the ends of the cable.

By this method, it can not test the connector on the far end of the under testing cable since it is not connected to another connector, and connection to a reference connector is necessary to make a connection loss measurement.

Test With Launch And Receive Cable
By placing a receive cable at the far end of the under testing cable, the OTDR can measure the loss of all factors along the cable plant no matter the connector, the fiber of cables, and other connections or splices in the cable under test. Most OTDRs have a least squares test method that can substract out the cable included in the measurement of every single connector, but keep in mind, this may not workable when the tested cable is with two end.

During the process you should always keep in mind to start with the OTDR set for the shortest pulse width for best resolution and a range at least twice the length of the cable you are testing. Make an initial trace and see how you need to change the parameters to get better results.

OTDRs can used to detect almost any problems in the cable plant caused during the installation. If the fiber of the cable is broken, or if any excessive stress is placed on the cable, it will show up the end of the fire much shorter than the cable or a high loss splice at the problem locations.

Except OTDR testing, the source and optical power meter method is another measurement which will test the loss of the fiber optic cable plant directly, The source and meter duplicate the transmitter and receiver of the fiber optic transmission link, so the measurement correlates well with actual system loss.

Using Network Tester To Identify Cable Problems

network tester is designed to calculate how well your high-speed network cables are performing. As you know, poor performance in these cables can result in damage to work, poor Internet access, and general disruption to the network.

Digital Network LCD Cable Test NS-DX

Main Features Of Network Tester
Network tester has 2 different boxes, which are separate. These boxes are the transmitter and receiver. A basic tester consists of a source of electrical current, a measuring device that shows if the cable is good, and a connection between the two, usually the cable itself.

Network cable tester can be a simple apparatus that merely identifies whether current flows through the cable, or it may be a professional-level, complex device that gives additional information that helps identify the problem. Professional-level network cable testers may not only tell if an open circuit exists, but may identify where the break is located. Some also identify the gauge of wire used and can generate their own signal to test for interference.

Common Problems Of Network Cables
There are a number of problems which can be sorted out by using the network tester, and it will certainly help you to save time trying to find software or hardware solutions.

If a network isn’t working correctly, the problem is frequently user error or other problems. It will rarely be a faulty cable. A network cable tester is more frequently used to tell whether a patch cable will work before it is connected. The cabling should first be examined visually to identify any obvious problems. If everything looks correct, a network cable testing device may then be used.

Basic network cable testers can test for simple connectivity issues but may not identify other problems that cause the cable to malfunction. Cabling may not work when it is near a source of interference or if the cable is too long. Intermittent faults may develop that do not show up when the cable is tested. Sometimes the problem is not sustained long enough to show up on the tester.

How To Use A Network Tester?
Step 1 – Connect the tester

Plug the network cable into both ends of the box, one into the transmitter, and one into the receiver. These boxes are a model of your computer network, so you should be able to easily locate which box is which. Make sure that your cables are fully plugged in before you proceed to the test.

Step 2 – Turn on the tester

Turn on the network cable tester device. The tester will send a signal from one end of the box to the other, and this will be the message which is relayed through the cable, much as would occur in your computer network. Keep the network cable tester connected to the cable at all times during the test, otherwise it will not work.

Step 3 – Read the report from the tester

While the message is being passed from one end of the cable to the other, the network cable tester will be examining the message for faults, and checking that the message has been properly received at the other end. If the tester concludes that this is not the case, and that something has gone wrong, you will find that the tester displays a number of red lights. The differences between the red lights and the green lights which mean that all is working well may not be the same from network cable tester to tester, but you should be able to work out exactly what the problem is with your cable by reading the instructions.

Step 4 – Read the problem

The different lights on your tester are used to send a signal to the person operating the machine. Your manual will give you a complete run-down of what the different patterns of lighting means, and if there is any problem with your cable that should be addressed. Once you have found the problem, remove the cable from the boxes, and return the tester to a safe place.

For cable testing, the network tester provides full cabling testing, displaying wire map, ID, and faults, including shorts, opens, miswires, split pairs, and reverses. The full featured network tester also measures cable length and generates tone levels for signal tracing and cable identification on all pairs, a selected pair, or a selected pin. Fiberstore is a professional manufacturer supplies all kinds of fiber optic tools, including network cable tester, cable stripperpunch down tool, telephone line tester, fiber cable stripper, cable crimping tool, etc.

Further Understanding Cable Fault Location

Our human are living in the environment that always be surrounded by light and electicity. Imagine a day when there is no electricity at home, the first idea come to us is there must be a fault need to be fixed. You should not only need to known what a cable fault is but also what kind of instruments needed to get you out of the bad situation. This article will give a brief introduction about cable fault location as well as the working process of a typical cable fault locator.

A cable consists of multiple wires or electric conductors that are held together with a covering. The cables are frequently used for the distribution of the electrical energy. Although they are most highly developed, there are still malfunction in the cable system. Cable fault location is such process of locating periodic faults, such as insulation faults in underground cables, and is an application of electrical measurement systems.

power cable fault locator from fiberstore

Cable Fault Location is the process of locating the short circuit faults, cable cuts, resistive faults, intermittent faults, and sheath faults. Power cable fault locator is designed to locate cable faults, pinpointing the fault location, route tracing, cable identification, voltage withstand test and cable information managementCable faults are damage to cables which effect a resistance in the cable. If allowed to persist, this can lead to a voltage breakdown. There are different types of cable faults, which must first be classified before they can be located.

Contact fault: There are two kinds of contact fault, one is the contact between conductor and screen will generating a varying resistance, the other is the contact between multiple conductors will also generate a varying resistance.

Sheath faults: Sheath faults refers to the damage of the cable sheath which allows the surroundings contact with the cable screen.

Moisture caused faults: Water penetrates into the cable sheath and contacts the conductors. Impedance changes at the fault location make measuring more difficult. The resistance usually lies in the low-ohmic range.

Voltage Disruptions: Voltage disruption is caused by the combination of series and parallel resistances, usually in the form of a wire break.

All of the fault listed above will either cause the breakout of the electric or a electric exceed. As we known each cable has a limit of power supply. When this limited exceeds, or the wires becomes weak, there will be a short circuit causing a spark and then a minor or major explosion. To fix this issue, a cable fault locator is needed. To locate a fault in the cable, the cable must first be tested for faults. During the cable testing, flash-overs are generated at the weak points in the cable, the cable will be fixed either by providing new wiring, or increasing the wire strength. During the working process of the cable fault locator, the cable fault finder receives signals from the locator and the arrow on the instruments points to the position where the digging and maintenance required to be done.

FiberStore now offers a full series of power cable fault locators that will automatically detect the cable fault, which will greatly reduce the time and training required to find these problems. Our cable fault location instruments systems are applicable to all types of cable ranging from 1 kV to 500 kV and all types of cable faults such as short circuit faults, cable cuts, resistive faults, intermittent faults, sheath breaking, water trees, partial discharges. Know more informations of exporters and suppliers of electric or fiber optic tester.

What Is A Fiber Optic Adapter

Fiber optic adapter, also called Fiber Optic Coupler, is a small device that used to terminate or link the fiber optic cables or fiber optic connectors between two fiber optic lines. A Fiber Adapter allows fiber-optic cables to be attached to each other singly or in a large network, allowing many devices to communicate at once. Fiber Optic Adapters are widely used in light distribution frame(ODF), optical fiber communications equipment, measuring appliance and so on.

Optical adapter comes in versions to connect single fibers together (simplex), two fibers together (duplex), or sometimes four fibers together (quad).

Most adapters are female on both ends, to connect two cables. Connecting two cables together can allow two devices to communicate from a distance through a direct connection with the fiber optic line. Some are male-female, which typically plug into a port on a piece of equipment. This then allows the port to accept a different connector than for which it was originally designed. We discourage this use because we find the adapter extending from the equipment is subject to being bumped and breaking. Also, if not properly routed, the weight of the cable and connector hanging from the adapter may cause some misalignment and a degraded signal.

Fiber optic adapters are typically connecting cables with similiar connectors (SC adapter to SC connector, LC adapter to LC Connector, etc.). Some adapters, called “hybrid”, accept different types of connectors (ST to SC, LC to SC, etc.). When attempting to connect two cables that are different shapes, it is necessary to use a hybrid connector.

There are also adapters that can be used to attach a bare fiber-optic cable to a Power Adapter. This piece allows the cable to fit into a connection slot, whether into a mating sleeve or into an electronic device. The fiber-optic cable can be fit into an adapter that works with any of the standard shaped connectors.

The fiber optic adapters are many types because of the diversity of the connectors. In order to realize the fluent fiber optic connection, the fiber optic adapter panel shapes or types should be in accordance with the fiber optic connectors or cables. Common shapes of the adapters are square, rectangular, or round that with FC, LC, ST, SC, MTRJ types. These simple types of adapters are often referred to as mating sleeves because they allow two cables to connect to one another. Some of these common line to line connectors are also built to connect three or four cables together.

There are also single mode and multimode fiber optic adapters or single mode and multimode fiber optic connections. They are designed for singlemode or multimode cables. The singlemode adapters offer more precise alignment of the tips of the connectors (ferrules). It is ok to use singlemode adapters to connect multimode cables, but you should not use multimode adapters to connect singlemode cables. This can cause misalignment of the small singlemode fibers and loss of signal strength (attenuation).

Flange fiber optic adapters are typically with ceramic sleeves, fitting for both single mode and multimode fiber optic connections. The adapters are in many different shapes, but they all serve the same purpose.

PCI Network Adapter acts as the interface between a computer and a fiber optic network cable. The purpose of the fiber optic network card is to prepare, send, and control data on the network. There are 100M, 1000M, and 10G fiber optic network card adapter available. Fiber network interface cards are available in both Multimode and Single-mode configurations with ST, SC, MTRJ, orLC connectors, and SFP for Gigabit.

Because the fiber adapters should fit the according connectors, the fiber optic adaptors sides and shape are made as per the connectors. Generally, ST adapter and FC adapter are metal body, LC, SC, MU, MTRJ, E2000 types are non-metal body. Single mode fiber optic adapters are with ceramic sleeves, multimode fiber optic adapters are bronze sleeves. But you can also use ceramic sleeve fiber optic adapters to link multimode connectors.

The Main Parameters of Cisco SFP Transceiver Modules

Cisco System, Inc. established in 1984, is an international reputable company providing internet solutions, equipment and software products, whose products are mainly used to connect a computer network system, Cisco routers, switches and other equipment carries 80% of global Internet communications, of the new economy in the Silicon Valley legend. Over the past 20 years, Cisco has almost become synonymous with the Internet, network applications, productivity, Cisco have become the market leader in every area of its entry. The company is also specialized in producing transceiver modules include a well advanced and useful type of transceiver namely mini GBIC or SFP module.

SFP is the abbreviation of Small Form Factor Pluggable referring to a compact small and hot-pluggable transceiver. Cisco SFP transceivers are designed to change the series electric signals to the serial optical signals for either telecommunication or data communication fields. The transceiver is usually working with a network device a switch or a router to connect to a copper networking cable or fiber optic. SFP is a recognized industry standard thus is supported by almost every leading vendors such as H3C, HP, Huawei. It is designed to support communication in standards such as Gigabit Ethernet, SONET, Fibre Channel and many others.

The main parameters of the SFP module

Average transmit optical power (TxLOP: Optical Average Power) average transmit optical power refers to the signal logic 1 when the optical power and for 0:00 the arithmetic mean of the optical power. P0 + the P1 PAVG = 2 (dBm)

Consumers light ratio (ER: ExtinctiRatio) signal logic to 1, the optical power and is 0 when the light power size ratio. The calculation formula for: P1ER = 10log P0 (dB) ER extinction ratio, the unit is dB, P1 and P0 represents the logic 1 and 0 when the optical power.

The minimum average light reception sensitivity (Receiver Sensitivity) measure the receiving end of a certain bit error rate (1 × 10exp (-12)) To ensure the desired reception power, in units of dBm. BER is within a longer period of time, after received after the receiving side of the photoelectric conversion error output terminal of the number of symbols with the BER tester gives the ratio of the number of symbols.

Loss indicative signal (LOS Assert) restore instruction (LOS Dessert) receiver output an electric signal, and the signal is lost and the potential level of the adequacy reflects the intensity of the optical signal received by the receiver, to determine by comparing the potential of the preset potentiometer light whether the signal is lost. Potential has a certain effect hysteresis comparator to achieve, usually default electrical signal corresponding to the optical power as an indication, in dBm

Eye mask margin (EMM: Eye Mask Margin) eye opening, refers to the degree of “open” in the best sampling point eye amplitude distortion-free opening of the eye diagram should be 100 [%]. Eye diagram template tolerance eye mask expansion, until the eye diagram of the sampling points into the template of the biggest expansion of the expansion area percentage.

Cisco SFP is flexible in its extensive set of items including Cisco GLC-T, Cisco GLC-SX-MM, Cisco GLC-LH-SM, Cisco CWDM SFP, which can be used with the union of 1000BASE-T, 1000BASE-SX, 1000BASE- LX/LH, 1000BASE-EX, 1000BASE-ZX, or 1000BASE-BX10-D/U in a port-by-port basis.