1. Introduction
The ORIENTEK Optical Fiber Identifier is a versatile tool designed for efficient and non-destructive detection of optical signals in fiber optic cables. It integrates multiple functions including Live Fiber Identification (OFI), Visual Fault Locator (VFL), and Optical Power Meter (OPM), along with an LED light for convenience in dark environments. This manual provides detailed instructions for the safe and effective use of your device.
2. Safety Information
- Laser Safety: The VFL function emits a visible red laser. Do not stare directly into the laser beam or view it with optical instruments. Avoid direct exposure to eyes.
- Battery Safety: Use only specified battery types (AA*2). Ensure correct polarity when installing. Do not mix old and new batteries or different types. Remove batteries if the device is not used for an extended period.
- Handling: Handle the device with care. Avoid dropping or subjecting it to strong impacts. Keep the device dry and away from extreme temperatures.
- Maintenance: Refer to the maintenance section for cleaning instructions. Do not attempt to disassemble or repair the device yourself. Contact qualified personnel for service.
3. Package Contents
Please check the package contents upon receipt. The standard package typically includes:
- Optical Fiber Identifier Unit (TFI-40V / TFI-45 / AFI-20V / TFI-35P)
- User Manual
- Carrying Case (may vary by model)
- For TFI-35 / TFI-35V / TFI-35P models: 4 pcs fiber holders (250μm, 900μm, 2mm, 3mm)
- For TFI-40V / TFI-45 / AFI-20V models: No separate fiber holders needed as they feature a multi-in-one fixture.
4. Product Overview
The Optical Fiber Identifier is designed for ease of use and portability. Key components and features include:

Figure 4.1: Functional Analysis of AFI-20V Optical Fiber Identifier
- Multifunctional Fixture: For TFI-40V / TFI-45 / AFI-20V models, this integrated fixture supports 0.25-3.0mm fiber types without needing to change fixtures.
- LED Display: Shows signal strength, direction, frequency, and OPM readings.
- Direction Indicator: Visual cues (left/right lights) to show signal transmission direction.
- LED Light: Built-in flashlight for working in dark environments.
- VFL (Visual Fault Locator): Integrated red laser for breakpoint location up to 5 km.
- Battery Cover: Located on the back for easy battery access.
- Fixture Switch/Trigger: Used to clamp the fiber and initiate testing.

Figure 4.2: Decaat AFI-20V Optical Fiber Identifier highlighting VFL, LED light, signal direction, and 3 signal frequencies.

Figure 4.3: Orientek TFI-35P High Precision Optical Fiber Identifier with OPM range indicators.
5. Setup
5.1 Battery Installation
- Locate the battery cover on the back of the device.
- Open the battery cover.
- Insert two AA batteries, ensuring correct polarity (+/-).
- Close the battery cover securely.
5.2 Fiber Holder (TFI-35 / TFI-35V / TFI-35P only)
For models TFI-35, TFI-35V, and TFI-35P, select the appropriate fiber holder (250μm, 900μm, 2mm, or 3mm) based on the fiber optic cable diameter you intend to test. Insert the chosen holder into the device's fixture slot.

Figure 5.1: Integrated VFL and LED lighting feature, showing the 'Open' mechanism for the VFL cap.

Figure 5.2: The AFI-20V device in hand, demonstrating its small and portable design for online testing.
6. Operating Instructions
The device features an ergonomic design for comfortable handling. To operate, hold the machine in hand, press the trigger switch on the back with your index finger, and clamp the fiber optic cable to automatically start the test.

Figure 6.1: Ergonomic design and how to clamp the fiber optic cable for testing.

Figure 6.2: TFI-45 Button icons and functions diagram.
6.1 Switch and OFI (Optical Fiber Identifier) Function
- Power On: Long press the power button to turn on the machine. The backlight will illuminate.
- Power Off: Long press the power button to turn off the machine.
- Backlight/LED Light: In the power-off state, short press the power button to turn on the backlight and the LED icon.
- OFI Mode: In the common state, the OFI function is enabled by default. The OFI icon and related results will be displayed on the screen. Short press to exit OFI function.
- Initiate OFI Test: In the off state, pull the trigger to automatically start the OFI test without needing to power on other functions.
6.2 OPM (Optical Power Meter) Function
- Activate OPM: In the power-on state, press and hold the OPM/dB/Ref button to turn on the OPM function. The OPM icon will appear on the screen, and the OFI function will be temporarily inactive.
- Switch Units/Reference: While in OPM function, short press the OPM/dB/Ref button to switch between units and set reference values.
- Switch Wavelength: Under OPM function, short press the wavelength button to cycle through available wavelengths.
- Return to OFI: Under OPM function, pull the trigger to automatically switch back to the OFI function. The OPM icon will disappear, and the OFI icon will display.
6.3 VFL (Visual Fault Locator) Function
- Activate VFL: In any state (power on or off), short press the VFL button to turn on the VFL function. The VFL icon will appear on the screen.
- Flashing Mode: Short press the VFL button again to enter the VFL flashing mode.
- Deactivate VFL: Short press the VFL button a third time to turn off the VFL function. The VFL icon will disappear from the screen.
6.4 Signal Direction and Frequency Identification

Figure 6.3: Universal fiber compatibility and signal direction indication. The left direction light indicates signal from right to left.

Figure 6.4: The device can identify 270Hz, 1KHz, and 2KHz signal frequencies, accompanied by a buzzer sound.
- Direction Indication: When an optical fiber has a signal, the left and right direction lights on the display will indicate the signal's transmission direction. For example, if the left light is on, the light source is from right to left.
- Frequency Identification: The device can identify 270Hz, 1KHz, and 2KHz signal frequencies. A buzzer sound will accompany the identification of these frequencies.
7. Maintenance
- Cleaning: Use a soft, dry cloth to clean the exterior of the device. For optical ports (VFL, OPM), use specialized fiber optic cleaning tools to ensure no dust or debris affects performance.
- Storage: Store the device in its protective carrying case in a cool, dry place away from direct sunlight and extreme temperatures.
- Battery Care: Remove batteries if the device will not be used for an extended period to prevent leakage and damage.
8. Troubleshooting
- Device not powering on: Check battery installation and ensure batteries are charged. Replace if necessary.
- No signal detected: Ensure the fiber is properly clamped in the fixture. Verify the fiber is live and carrying a signal. Check for dirty or damaged fiber ends.
- Inaccurate OPM readings: Clean the OPM port. Ensure the correct wavelength is selected for measurement.
- VFL not working: Check if the VFL cap is open. Ensure the VFL function is activated as per instructions.
- Buzzer not sounding for frequency: Ensure the signal frequency is within the detectable range (270Hz, 1KHz, 2KHz).
9. Specifications

Figure 9.1: Detailed product parameters including OFI, VFL, and OPM functions.
| Parameter | Value |
|---|---|
| Wavelength Range | 800-1700nm |
| Signal Recognition Type | CW, 270 Hz ±5%, 1 kHz ±5%, 2 kHz ±5% |
| Detector Type | 1mm InGaAs 2 pcs |
| Adapted Fiber Type | φ0.25 (bare fiber), φ0.9, φ2.0, φ3.0 |
| Signal Direction | Direction indicator display signal transmission direction |
| Optical Power Reading Range | -40 dBm to 10 dBm |
| Signal Frequency Range | 270Hz, 1kHz, 2kHz |
| Power Type | AA*2 |
| Operating Temperature Range | -10°C to 60°C |
| Storage Temperature Range | -25°C to 70°C |
| Dimension/Weight | 219*45*28mm / 235g |
| Parameter | Value |
|---|---|
| Power Range | 10mW |
| Testing Distance | 3-5km |
| Wavelength | 650nm |
| Laser Type | LD |
| LED Light | Support |
| Parameter | Value |
|---|---|
| Wavelength Range | 800-1700 |
| Measurement Range (dBm) | -70~+6 dBm / -50~+26dBm |
| Standard Wavelength | 850, 980, 1300, 1310, 1490, 1550, 1625 |
| Optical Connector | 2.5mm universal interface + SC |
| Detector Type | InGaAs |
10. User Tips
- Fiber Holder Selection: If you have a TFI-35, TFI-35V, or TFI-35P model, ensure you select the correct fiber holder size (250μm, 900μm, 2mm, or 3mm) for the fiber you are testing to ensure accurate readings and prevent damage. Models TFI-40V, TFI-45, and AFI-20V feature a universal fixture that adapts to various fiber sizes without needing separate holders.
- Non-Destructive Testing: The identifier uses micro-bending technology for non-destructive testing, meaning it won't interrupt live traffic on the fiber.
11. Warranty and Support
This ORIENTEK Optical Fiber Identifier comes with a 1-year warranty from the date of purchase. ORIENTEK also provides free technical support for the entire product lifespan.
For technical assistance, troubleshooting, or warranty claims, please contact ORIENTEK customer service through the official channels provided at the time of purchase or on the ORIENTEK website.