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Product Description


GAOTek handheld OTDR is specially designed and developed for daily maintenance, troubleshooting, repair of the basic optical fiber. It is equipped with original concept, simplified operation and high measurement accuracy so as to meets the need of fast troubleshooting and fault finding and help to do the troubleshooting and maintain the fiber optics network. It is the most practical tools for the field workers to maintain the optical fiber currently. This instrument is applied in FTTx, fiber optics network engineering, verification, commissioning and maintenance as well as in the R&D and production test of fiber.

Key Features

  • Handheld, portable, light weight and easy to operate for out-door applications
  • Supported wavelength : SM 1310 nm/1550 nm
  • Meausring fiber length, point distance, loss and attenuation index
  • Measuring fiber reflectance loss and connectors insertion loss
  • Locate Macrobend
  • Supply with interchangeable connectors
  • Auto and manual test mode available
  • Display real-time fiber status
  • Display the trace info and test parameters in summary, event and trace
  • Only one Q Key for fast measurement
  • Pre-set threshold and varify results by Pass/Fail
  • IP ping test to verify the network connectivity
  • Integrated VFL to fast locate the fault position
  • Optimized arithmetic for fast locating the fiber fault or break position
  • Test duration selectable (Min. 5s)
  • 5 inches color capacitance touchscreen, menu-driven operation, friendly GUI
  • Multiple touch gestures : moves up/down/left/right, single/double click etc.
  • Touch and keypad operation modes, freely to zoom in/out to locate the trace
  • Store up to 1000 traces
  • Equipped with professional PC software Test/Managerplus to view test results
  • Test results can be upload to PC through USB or Ethernet port for further professional analysis, generating reports or printing.
  • Output test in HTML, Excel and PDF files
  • Upgrade latest embedded software for free when availabe with new version

Technical Specifications

Wavelength 1310 nm/1550 nm
 Dynamic range 32/30 dB
Pulse width 5/10/30/100/300/1000/3000/10000ns
Event Dead Zone 4.27 ft. (1.3 m)
Attenuation Dead Zone 18.04 ft. (5.5 m)
Linearity ±0.3dB/dB
Sampling Resolution 0.08 – 2.5
Sampling point max 64000
Distance Uncertainty ±(1+0.005 % x distance + sampling resolution
Distance Range 0.40 mi to 99.42 mi. (0.65 km to 160 km)
Real time Refresh Frequency 2Hz
Memory Capacity 1000 traces
Test Duration Max 180 s
LD Emitting Power 1310 nm/1550 nm: 110 mW/80 mW
VFL 650 (±10) nm 1Hz or CW
Dimension 9.84 in x 4.33 in x 2.75 in (250 mm x110 mm x70 mm)
Weight 2 lbs. (0.95 kg)
Battery Working time 8 to 16 Hours
Working Temperature 14 ◦F to 122 ◦F (-10 ◦C to 50 ◦C)
Storage Temperature -14◦F to 158 ◦F (-40 ◦C to 158 ◦F)
Humidity 0 % to 95 % non- condensing

Additional Specifications:

Typical Application: OTDR can be applicable in

  • Short-link testing
  • Service Activation
  • Fault Finder
  • Troubleshooting (dark fiber)

Ordering information

 After all the functions of the OTDR are fully understood, user could start to purchase the instrument on demand.

When user has received the instrument, please check it and its accessories carefully to make sure whether the received one has met the purchasing requirement or not.

Standard configuration list of OTDR:

Item Qty Item Qty
OTDR 1 Waterproof Package 1
Interchangeable Connector 1 User Guide 1
USB Communication cable 1 Quality certificate card 1
AC charger 1 Maintenance card 1
Li-ion Rechargeable Batteries (built in) 1 Packaging list 1
Test manager plus setup CD(user Manual included) 1    

 Product Compositions:

Compositions of Instrument

The OTDR is consisted of following modules:

  • Hardware: Main board, inner fiber
  • Software: The Embedded software, surveillance and Management PC software “TestManagerPlus”
  • Accessories: Waterproof Package, Interchangeable connector, AC charger, etc

Appearance of Instrument

The appearance of the instrument is as:

  • Font Panel: LCD display, LED indication, Keypad
  • Back panel: S/N tag, Battery house
  • Upper end: SM connector and VFL connector
  • Right end: Mini USB port and USB port
  • Left end: Ethernet RJ45, Power input jack

Touch Screen

Touch-screen is quite intelligent and easy to use. Operators can transmit the order and achieve function control by touching the screen. Touch screen is much more convenient compared with traditional keyboard input and mouse input.

The Touch screen adopts capacitive screen and has many advantages as follows high resolution and good transparency, good intense light-resistant and super short response time, high stability, once calibrate, never slip.

Getting Started

After product composition it is time to understand the unpacking check, LED Keypad indicators and keypad, switch-on/off, power supply, battery and charge, communication with PC for the instrument, cleaning and connecting optical fibers and safety precautions for the operators.

Unpacking Check

In order to safety transport, the OTDR is packaged with a paper carton and with all accessories placed in a waterproof package. Please check when receive the product.

  • If the packing carton is impaired and if the appearance of the product is impaired
  • If the instrument and all its accessories are available

Keypad and LED indicators

The OTDR has four keys:

The Left one is for power indication and it will turn on when the OTDR is switched on, while the right one is for working indication, it turns on when the OTDR is under testing.


Under normal conditions, the OTDR can be used immediately when switching on. When switching off, the OTDR will keep the following parameters in its internal memory.

  • Test parameters
  • User-defined thresholds
  • Regional, LED and power-saving settings
  • Saved test results

To switch on the OTDR:

Press the power key for a few seconds and then release it. The OTDR will be switched on and show the main menu.

To switch off the OTDR:

When the OTDR is in working, press the power key, the LCD will turn on, and press again and the LCD will turn off.

Power supply

The supplied AC charger is specially designed and customized for the OTDR.

Please use the supplied AC charger when operating with the instrument or charging the battery. Here are the specifications of the AC charger.

AC input: 100V-240V, 50/60Hz, 0.5A

DC output 8.4V, 1200mA

Rechargeable battery and charging

  • The instrument applies large volume rechargeable Li-ion battery. Do not use a non-standard charger to charge the instrument, or else the battery may be explosive
  • If you need to apply external power supply for operation, please do use the standard Li-ion charger the vender supplies
  • Connect the OTDR to a power outlet by using the AC charger, and it will be charging automatically. The AC charger can also supply power to the instrument directly
  • The standard charger has an external charging circuit, so the instrument can be working while charging. When charging, the LED indicator on the charger turns on in red and turns green when finishing recharging
  • A new rechargeable battery can be charged and discharged for about 500-800 times, and then it cannot be used any more. Normally the fully charged batteries could support the instrument continuous working for 8-16 hours depending upon the test settings. So when the operating duration of the battery is significantly reduced, the battery should be replaced. The recommended duration is one or two yrs. to replace the battery
  • Method of replacing battery: Switch off the instrument, open the kickstand on the back, unscrew the screws on the back to remove the battery box cover, you can see the battery in the house. Pull out the battery wire to take out the battery. Plug the new battery wire to the jack inside the battery box, put the new battery in, and put the battery wire in the gap between and the box. Cover the battery box and tighten the

Communication with PC

The instrument supports communication with PC through USB or Ethernet port with help of TestManagerPlus software. TestManagerPlus can do two jobs, one is to upload the test results stored in the instrument to PC for further processing including filing, printing and analyzing and the other is to upgrade the embedded software via PC to protect your investment.

Communication steps

  • Switch off the OTDR firstly
  • Connect USB or Ethernet RJ45 port of the OTDR to PC with USB or Ethernet cable
  • Switch on the OTDR
  • Enable USB or Ethernet port in System to PC Communication menu
  • Run the TestManagerPlus software on PC and click on Connect button on the tool bar. After the successful connection, the user can upload, view, analyze, delete, print test results in the form of report and do other operations
  • Switch off the OTDR after communication with PC
  • Pull out the USB or Ethernet cable

Cleaning and Connecting Optical Fiber

  • Clean the fiber ends as follows
  • Gently wipe the fiber end with a lint free swab dipped in isopropyl alcohol
  • Use compressed air to dry completely
  • Visually inspect the fiber end to ensure its cleanliness
  • Carefully align the connector and port to prevent the fiber end from touching the outside of the port or rubbing against other surfaces. If the connector features a key, ensure that it is fully fitted into the port’s corresponding notch
  • Push the connector in so that the fiber is firmly in place, thus ensuring adequate contact. If the connector features a screw sleeve, tighten the connector enough to firmly maintain the fiber in place. Do not over-tighten, as this will damage the fiber and the port.

Safety Precautions

  1. Instrument safety information

The following general safety precautions must be observed during all phases of operations, service and repair of this instrument. Failure to comply with these precautions or with specific warnings and safety standards of designs, GAOTek assume no liability for the customer’s failure to comply with these requirements

  1. Laser Safety Information

The instrument is a class 3R laser product in compliance with standards. It is potentially harmful in direct intrabeam viewing.

Navigating the Displays

There are five main operating menus in details:

  • “OTDR” Menu
  • “VFL” Menu
  • “Network tools” Menu
  • “Storage” Menu
  • “System” Menu

Menu Overview

The operating menus of the OTDR are composed of five functional modules, including three testing modules and two additional modules. The testing modules include OTDR, VFL, Network tools and the additional modules include storage and system menu.

  • “OTDR” Menu

After clicking OTDR on the main menu, it will get into the settings menu. It includes test mode, wavelength, range, pulse and one check box Auto save result. Once these items are set click other settings and will be seen such as general parameters, Acquisition Parameters, Analysis Parameters, Pass/Fail, Thresholds, Macro bend Parameters and storage settings

Setting General OTDR Parameters

OTR general parameters can be set such as:

  • Display trace grid: after selecting this item, the trace grid can be displayed or hidden on the graph’s background. By default, this item is selected.
  • Zoom and markers: the zoom controls and the markers appearing on the graph can be displayed or hidden
  • Auto zoom fiber span: it can be set to display the trace between the span start and span end. This feature is enabled by default. Even if the fiber span is zoomed in automatically, it can be adjusted manually. Events outside the fiber span can be zoomed in as well.
  • Reference file: The selection of a reference trace can be enabled or disabled. A reference trace is used to compare-fiber of a same cable, monitor fiber deterioration, or compare fiber before and after installation.
  • Summary pane: By default, the summary pan is automatically displayed as soon as an acquisition is complete. This automatic display can be disabled.
  • Show event sections: Event (fiber) sections can be displayed or hidden in the Events pane, depending on the types of values to be viewed. If event sections are displayed, the Events pane will include section length and section attenuation

Setting the Acquisition Parameters

Some parameters such as IOR (group index), Backscatter, and Helix Factor can be set in the OTDR. Also the First Connector Check can be enabled or disabled.

The OTDR contains default IOR (group index), backscatter and helix factor values and these values can be modified if they do not suit the testing needs. Before performing tests, make sure that the settings of these parameters are correct.

Setting Analysis Parameters

To define the actual fiber span start, the Launch fiber length can be set. When performing tests with the OTDR, a launch fiber between OTDR and the fiber under test is generally connected. That is why, by default, the fiber span includes the launch fiber. When defining the length of the launch fiber, the application sets the fiber span start at the beginning of the fiber under test. Therefore, only events related to the defined fiber span will be taken into account.

The application will include the loss caused by the span start event in the displayed values.

The span start event will also be taken into account when determining the status (pass/fail) of connector loss and reflectance

Splice Loss: To display or hide small non-reflective events.

Reflectance: To hide false reflective events generated by noise, transform non-harmful reflective events into loss events, or detect reflective events that could be harmful to network and other fiber-optic equipment.

End-of-fiber: To stop the analysis as soon as an important loss event occurs.

Setting Pass/Fail Thresholds

Thresholds can be defined to specify acceptable values (in dB) for Splice Loss, Connector Loss, Reflectance, Span Loss and Span ORL, and this, for each wavelength.

Each time a measurement exceeds a threshold, the result will be displayed by the word

“FAIL” in the Summary pane.

Setting Macro bend Parameters

The OTDR can locate Macro bend by comparing the loss values measured at a certain location, for a certain wavelength (such as 1310 nm) with the loss values measured at the corresponding location, but for a greater wavelength (such as 1550 nm). The OTDR will identify a Macro bend when comparing the two loss values if: Of the two loss values, the greater loss occurred at the greater wavelength. The difference between the two loss values exceeds the defined delta loss value. The default delta loss value is 0.5dB. Also the macro bend detection can be disabled.

Storage Settings

In this menu, the name of auto-saving file can be set with prefix and suffix part respectively

“VFL” Menu

The VFL helps identify bends, faulty connectors, splices and other causes of signal loss.

From its dedicated port, the VFL emits a red signal which becomes visible at the location of a fault on the fiber. The signal can be continuous (by default) or blinking (1Hz).

The VFL status is indicated by pressing the VFL button in the main menu and then selecting in the menu.

To activate VFL and inspect a fiber:

  1. Connect the fiber under test to the VFL port
  2. Press the VFL button in main menu

Select VFL “On” to switch on the VFL

  1. Select “Continuous” or “Blink”
  2. Inspect the fiber, but do not look directly into the beam. If the light is coming out of

the rubber jacket or on the side of the ferrule, the fiber is defective.

  1. Select VFL “Off” to switch off the VFL

“Network Tools” Menu

After pressing Main Menu key and clicking “Network Tools”, two items will be seen: Ping and Trace Route.

  • “Ping”

On the menu it provides setting of IP Address, Target Address, Ping Counts, and Data


The IP Address can be set in “System” “Network Settings” ”Specify the IP manually”. Other three items can be set on the menu directly. After settings, click Start button, and it will show the ping results.

  • “Trace Route”

On the menu it provides setting of IP Address, Target Address, and Max Hops

The IP Address can be set in “System”  “Network Settings” ”Specify the IP manually”. Other three items can be set on the menu directly.

After settings, click start button, and it will show the trace route results.

“Storage” Menu

Storage menu provides the storage of all save test results in the instrument. You can view all the saved history records in this menu.

Some operations on the test records can be performed according such as View, Rename, Delete, Check All and Export Data

“System” Menu

System menu provides settings or information of Network Settings, PC Communication,

U-Disk Upgrade, Factory Default Settings, Time & Date, Miscellaneous, and Instrument Information.

  • “Network Settings” Menu

On this menu, the IP address can be set for PC communication, or for Ping or Trace Route Test.

  • “PC Communication” Menu

PC Communication enables the communication between the instrument and PC. When

Customer need to upload the test results to PC; please enable the USB port or Ethernet port firstly.

  • “U-Disk Upgrade” Menu

This instrument can be connected to U-Disk directly for upgrading embedded software.

After putting the upgrade file in the U-Disk, connect it to the instrument through USB port and upgrade it to the latest version.

  • “Factory Default Settings” Menu

When clicking this button, it will restore to the factory default settings. Please do not perform this operation if not necessary because it would delete all your test records.

  • “Time & Date” Menu

To set the time and date:

  1. Enter main menu by pressing main menu key
  2. Select “System” ”Time & Date”
  3. Click the editable boxes and modify the settings
  • “Miscellaneous” Menu

This menu provides settings on Auto Power Off, Auto Screen Off, Beep on Alarm, Brightness, and Languages.

To set the time for Auto power off and Auto screen off:

  1. Enter main menu by pressing main menu key
  2. Select “System” “Miscellaneous”
  3. Set the time for auto power off and auto LCD off

Performing Measurements

This includes Full details of the measurements

  • Testing under auto mode
  • Testing under manual mode
  • Testing under real-time mode

 Testing under Auto Mode

The application will automatically evaluate the best settings according to the fiber link currently connected to the OTDR. By default, fiber characteristics will be evaluated each time when the tests are performed. This feature is very useful when another link of different length is tested with the same settings.

If it is intended, the OTDR will keep the same settings (range and pulse) for all acquisition.

If several similar fibers in the same cable require to test, this feature is particular practical when the clock can be set on resetting fiber.。

 To acquire traces under Auto mode:

  1. Clean the connectors properly
  2. Connect a launch fiber between the device under test and the OTDR port. Set the launch fiber length if necessary
  3. Click “OTDR” in the main menu, and get into setting menu
  4. Select “Auto” as the testing mode
  5. Select “SM 1310nm” or” SM 1550nm”
  6. Select test duration
  7. Select whether to keep settings same as acquisition and whether auto save results
  8. Press Q key to start testing, and click again to stop testing at any time

 Testing under Manual Mode

Distance range, pulse, and duration of acquisition can be set under this mode.

Note: Not all pulse widths are compatible with all wavelengths.

To acquire traces under Manual mode:

  1. Clean the connectors properly
  2. Connect a launch fiber between the device under test and the OTDR port. Set the launch fiber length if necessary
  3. Click “OTDR” in the Main menu, and get into the settings menu
  4. Select “Manual” as the testing mode
  5. Select “SM 1310 nm” or” SM 1550 nm”
  6. Select distance range
  7. Select pulse width
  8. Select test duration
  9. Select whether to auto save results
  10. Press Q key to start testing, and click again to stop testing at any time

 Testing under Real-time Mode

Fiber can be monitored at one wavelength at a time.

 To monitor fiber under Real-time mode:

  1. Clean the connectors properly
  2. Connect a launch fiber between the device under test and the OTDR port. Set the launch fiber length if necessary
  3. Click “OTDR” in the main menu, and get into setting menu
  4. Select “Real-time” as the testing mode.
  5. Select “SM 1310 nm” or ”SM 1550 nm”
  6. Select distance range
  7. Select pulse width
  8. Select whether to auto save results
  9. Press Q key to start testing, and click again to stop testing at any time

Managing Test Results

This is to help manage the test results.

  • Summary pane
  • Trace pane
  • Trace info pane
  • Button operations
  • Help menu
  • Open reference trace
  • Save trace files
  • Uploading results to PC

 Summary Pane

The pane is displayed immediately once the test completes. It will show tested wavelengths, Pass/Fail info, fiber length under test, macro bend info, etc.

Trace Pane

Trance pane will show the event and trace completely. And relevant operations such as zoom in/out can be performed.

Trace Info Pane

Details about the acquisition can be viewed after acquiring a trace. It also includes information about the tested fiber and job, or adding comments. This information is saved along with the trace.

Some information like marker A and B, cable ID, fiber ID is common for all wavelengths.

While some information like task, customer, and note is only available in current wavelength.

If customer wants to add or delete the information in trace info pane, you must modify the common information of all wavelengths. However, in such case, only the special information of current wavelength is modified. He must add or delete the information for other wavelengths manually.

After inputting the required information, it can be saved as the mask, with which it can be applied to all wavelengths in next acquisition and does not need to repeat the input.

Help Menu

To view the details of the trace clearly, operations such as zoom in/out, move up/down/left/right on the trace can be performed through zoom controls. This OTDR provides the instructions on how to perform buttons and gestures operations by clicking on help.


Operate the trace through different hand slides, and you will see what you want from the trace accordingly,

Open Reference Trace

Maximum two traces are shown on the menu: one is current trace, and another is reference trace (if it is selected). You can open the reference trace and make a comparison with the current trace.

Trace saved in .sor format can be viewed directly in this OTDR.

Enabling Reference Trace

  • Click “OTDR” in main menu, and then click “Other Settings”
  • Click “General Parameters”, and enable the item “Open Reference”

Open Reference Trace

  • In the trace pane, click icon
  • Select one trace saved in the OTDR, and then click “OK”, the reference trace will be shown on the menu in Blue icon
  • Click again the icon, and the reference trace will be closed.

Save Trace Files

If you do not enable the item “Auto Save Results” before testing, after each testing, it will notify you whether to save the result before you want to perform another testing, or return to previous menu. If you enable the item “Auto Save Results”, the traces will be saved automatically with default file name after test completes.

Uploading Results to PC

Test results can be expected to flash memory or PC, and the files in flash memory or PC can be transferred to OTDR as well.

OTDR has two types of USB ports:

  • USB port: Connect USB flash memory or PC
  • Mini USB port: Connect OTDR and PC through USB cable for transferring data

There are three ways to export test results to PC:

  • Export to flash memory
  • Export to PC directly through USB cable
  • Export to PC directly through Ethernet cable

1) Export to flash memory

  • Connect the flash memory to the OTDR through USB port
  • Click “System” in the main menu, and then click “Export results”
  • After the flash memory is detected, click “Export” and export data
  • Connect the flash memory to PC for transferring data

2) Export to PC directly through USB cable (require TestManagerPlus

  • Connect the OTDR with PC through provided USB cable
  • Switch on OTDR, and run TestManagerPlus software on the PC
  • Click “Connect” on the tool bar, and then select “USB”
  • It will prompt “connect successfully” when it is successfully connected
  • Then click “Upload”, and start to transfer the results to PC
  • After the process completes, click the record and view in details

3) Export to PC directly through Ethernet cable (require TestManagerPlus

  • Connect the OTDR with PC through provided Ethernet cable
  • Switch on OTDR, and run TestManagerPlus software on the PC
  • Click “Connect” on the tool bar, select “NET”, and then input the correct IP Address
  • It will prompt “connect successfully” when it is successfully connected
  • Then click “Upload”, and start to transfer the results to PC
  • After the process completes, click the record and view in details

Software Functions

TestManagerPlus communicates with series instruments via USB port or Ethernet port in PC. It can support uploading the stored data from the instrument, viewing and printing the stored results. Every test result on the PC can be easily checked, managed and analyzed further. It also can describe all the events happened in the test period time in details and help in classification, filing and report outputting of the test results. Another very important function of TestManagerPlus is that you can upgrade the embedded software in the instrument with this PC software automatically.

Basic functions of TestManagerPlus:

  • Connect the instrument
  • Upload the test results stored in the instrument
  • View the stored results
  • Analyze the stored results
  • Clean up the uploaded records
  • Print the test results in report file
  • Upgrade the embedded software
  • Help

System Configuration and Running Environment Firmware

Basic Configuration Required:

  • PC: 586/133MHz or better
  • Memory: 512MB or above
  • Hard disk: 500MB or above
  • CD-ROM drive for installation
  • Standard mouse and keyboard
  • USB/Ethernet port
  • Windows-compatible printer
  • Network card and cable


Basic Configuration Required:

  • Operating system: Windows 2003/XP/VISTA/WIN7

System Configuration Recommendation

  • System display mode: 600×800 Pixels
  • Install the printer before setup

Install and Uninstall the Software on the PC

Installation Process

  • Open the package and take out the CD disk with the mark of “TestManagerPlus”
  • Switch on the computer
  • Insert the CD into the CD-ROM drive
  • View the contents of the CD from “My Computer”
  • Double-click “Setup.exe”
  • Complete the installation according to the setup wizard
  • After completing installation of the software, one short-cut icon
  • “TestManagerPlus” will be placed on the desktop automatically
  • Double-click the icon “TestManagerPlus” to run the program

 Uninstall TestManagerPlus

  • From the “Start” menu, choose “Settings”
  • Open “Control Panel”
  • Click “Add/Remove Programs”
  • Select “TestManagerPlus” in the list
  • Click “Change/Remove” button to remove the software automatically

How to Use TestManagerPlus

Connect the Instrument and operate

This instrument supports communication with PC through USB or Ethernet port with help of TestManagerPlus software and TestManagerPlus can do two jobs: one is to upload the test results stored in the instrument to PC for further processing including filing, printing and analyzing, and the other is to upgrade the embedded software via PC to protect your investment.

  • Connect the PC with instrument through USB cable or Ethernet cable
  • Enable “USB” or “Ethernet” port in “System” “PC Communication” in the OTDR
  • Run TestManagerPlus software, and click “Connect” on the tool bar, then select “USB” or “NET”, if the “NET” is selected, you should input the IP address same as the one in the instrument accordingly. After connecting successfully, operations like upgrading embedded software, transferring, viewing, analyzing, deleting, printing results can be performed.

 TestManagerPlus Software Operation

Graphic windows help you operate TestManagerPlus software simply and easily. You can work with TestManagerPlus.

Upgrading the Embedded Software

Manufacturer will launch the latest version embedded software and host software

TestManagerPlus in the website for the users to download. Make sure to visit the website frequently to ensure you will always get the software of latest version.

For the software upgrading method, please refer to the relevant part of “Communication with PC”


In this section customer understands how to maintain the instrument, clean EUI connectors and detector ports.

Trouble-free operations

Cleaning EUI connectors

Cleaning detector ports

Trouble-free Operations

To help ensure long, some trouble-free operations here to be followed:

  • Clean the fiber connector before using it.
  • Keep the OTDR away from dust.
  • Clean the OTDR outlet and front panel with a cloth slightly dampened with water.
  • Store the OTDR at room temperature in a clean and dry area, and avoid direct sunlight.
  • Avoid high humidity or significant temperature fluctuations.
  • Avoid unnecessary shocks and vibrations. If any liquids are spilled on or into the OTDR, turn off the power immediately and let it dry completely

Cleaning EUI Connectors

Cleaning EUI connectors will help maintain optimum performance. When cleaning, there is no need to disassemble the OTDR.

Cleaning Detector Ports

Cleaning detectors will help maintain measurement accuracy.

To clean detector ports:

  1. Remove the protective cap and the AC charger from the detector.
  2. If the detector is dusty, blow dry with compressed air.
  3. Being careful not to touch the soft end of the swab, moisten a cleaning tip with only one drop of isopropyl alcohol.
  4. While applying light pressure (to avoid breaking the detector window), gently rotate the cleaning tip on the detector window.
  5. Repeat step 4 with a dry cleaning tip or blow dry with compressed air.
  6. Discard the cleaning tips after use.


This section is intended to provide prompt help to operator on some frequently asked questions and the resolutions.

1The instrument cannot be powered on.

  • When “Low Battery” alarms, the instrument will be shut down soon automatically
  • When the voltage of battery drops to a low level, the power circuit of the instrument will be locked and cannot be opened until, Plug the Charger into an appropriate AC wall outlet and press “Power” key
  • When the battery is fully charged, unplug the Charger and press the “Power” key to switch on the instrument. And the instrument will work normally

2) The instrument shuts off.

  • Check if the voltage of battery is low
  • Check if “Power” in “System” “Miscellaneous” is set to ON or not

3) Duration of battery is getting shorter.

The usage life time of new rechargeable battery is about 500~800 cycles of charge and discharge. When you find the working duration is reduced in evidence, you should replace the rechargeable batteries.

Descriptions of Event Types

This describes all types of events that may appear in the events table generated by the application.

  1. Each type of event has its own symbol.
  2. Each type of event is represented by a graph of a fiber trace, which illustrates the power reflected back toward the source as a function of distance.
  3. An arrow points to the location of the event type in the trace.
  4. Most graphs show one complete trace, an entire acquisition range.
  5. Some graphs show only a portion of the entire range to view events of interest more closely.

Span Start

The Span Start of a trace is the event that marks the beginning of the fiber span. By default, the Span Start is placed on the first event of a tested fiber (typically the first connector of the OTDR itself).

Span End

The Span End of a trace is the event that marks the end of the fiber span. By default, the

San End is placed on the last event of a tested fiber, and is called the end-of-fiber event.

Also another event can be made as the end of the span to be focused analysis on. This will set the end of the events table at a specific event along the trace.

Continuous Fiber

OTDR Appendix B

  • 72-0166-00 67

This event indicates that the selected acquisition range was shorter than the fiber length.

The fiber end was not detected because the analysis process ended before reaching the end of the fiber.

The acquisition distance range should therefore be increased to a value greater than the fiber length.

There is no loss or reflectance specified for continuous fiber events.

End of Analysis

OTDR Appendix B

  • 72-0166-00 68

This event indicates that the pulse width used did not provide enough dynamic range to get to the end of the fiber.

The analysis ended before reaching the end of the fiber because the signal-to-noise ratio was too low.

The pulse width should therefore be increased so the signal reaches the end of the fiber with a sufficient signal-to-noise ratio.

There is no loss or reflectance specified for end-of-analysis events.

Non-Reflective Event

This event is characterized by a sudden decrease in the Rayleigh backscatter signal level.

It appears as a discontinuity in the downward slope of the trace signal.

This event is often caused by splices, Macrobend, or microbends in the fiber.

A loss value is specified for non-reflective events. There is no reflectance specified for this type of event.

If thresholds are set, the application indicates a non-reflective fault in the events table, whenever a value exceeds the loss threshold.

Reflective Event

Reflective faults appear as spikes in the fiber trace. They are caused by an abrupt discontinuity in the index of refraction.

Reflective events cause a significant portion of the energy initially launched into the fiber to be reflected back toward the source.

Reflective events may indicate the presence of connectors, mechanical splices, or even poor-quality fusion splices or cracks.

A loss and a reflectance value are normally specified for reflective events.

When the reflective spike reaches the maximum level, its top may be clipped due to the saturation of the detector. As a result, the dead zone—or minimum distance for making a detection or attenuation measurement between this event and a second nearby —may be increased.

If the thresholds are set, the application indicates a reflective fault in the events table, whenever a value exceeds reflectance or connector loss threshold(s).

Positive Event

This event indicates a splice with an apparent gain, due to the junction of two fiber sections having different fiber backscatter characteristics (backscatter and backscatter capture coefficients).

A loss value is specified for positive events. The loss specified does not indicate the true loss of the event.

The true loss has to be measured by performing bidirectional fiber measurements and bidirectional analysis

Launch Level

This event indicates the level of the signal launched into the fiber.

The figure above shows how the launch level is measured.

A straight line is plotted using least-square approximation to fit all trace points in the linear area between the first and the second detected events.

The straight line is projected toward the Y (dB) axis until it crosses the axis.

The crossing point indicates the launch level.

In the events table indicates that the launch level is too low.

Fiber Section

This symbol denotes a fiber section with no event.

The sum of all fiber sections contained in an entire fiber trace equals the total fiber length. Detected events are distinct—even if they cover more than one point on the trace.

A loss value is specified for fiber section events. No reflectance is specified for this type of event.

Each fiber section has its own length, attenuation and loss value.

Merged Reflective Event

This symbol denotes a reflective event combined with one or more other reflective events.

It also indicates the total loss produced by the merged reflective events following it in the events table.

A Merged Reflective Event is composed of reflective events. Only the Merged

Reflective Event is displayed in the events table, not the reflective sub events composing it.

Reflective events may indicate the presence of connectors, mechanical splices, or poor-quality fusion splices or cracks.

A reflectance value is specified for all merged reflective events and indicates the maximum reflectance for the merged event. A reflectance vale, corresponding to the highest reflectance value among all sub events composing the Merged Reflective Event, is also displayed.

The total loss (dB) produced by the events is measured by plotting two straight lines.

The first line is plotted by fitting, through least-square approximation, trace points in the linear area preceding the first event.

The second line is plotted by fitting, through least-square approximation, trace points in the linear area following the second event. If there were more than two merged events, this line would be plotted in the linear area following the last merged event.

This line is then projected toward the first merged event.

The total loss(△ dB) equals the power difference between the point where the first event begins (point A) and the point on the projected straight line located just below the first event (point B).

No loss value can be specified for the sub events.


This symbol indicates that an echo has been detected after the end of the fiber.

In the example above, the launched pulse travels up to the end connector and is reflected back toward the OTDR. Then, it reaches the second connector and is reflected again toward the end connector. It is then reflected back to the OTDR.

The application interprets this new reflection as an echo because of its characteristics (reflectance and particular position with respect to other reflections)

The distance between the second connector reflection and the end connector reflection is equal to the distance between the end connector reflection and the echo.

There is no loss specified for echo events.

Reflective Event (Possible Echo)

This symbol indicates a reflective event that can be a real reflection or an echo produced by another stronger reflection located closer to the source.

In the example above, the launched pulse hits the third connector, is reflected back to the OTDR and reflected again into the fiber. It then reaches the third connector a second time and is reflected once more to the OTDR.

The application would therefore detect a reflective event located at twice the distance of the third connector. Since this event is almost null (no loss), and since its distance is a multiple of the third connector distance, the application would interpret it as a possible echo.

A reflectance value is specified for reflective events (possible echo).