1. Introduction
This manual provides detailed instructions for the safe and effective use of the QIIRUN TMOFI-401 Live Fiber Optical Identifier with Visual Fault Locator (VFL). This device is designed for non-destructive fiber identification and fault location in optical fiber networks. Please read this manual thoroughly before operation and retain it for future reference.
2. Safety Information
Observe the following safety precautions to prevent injury and damage to the device:
- Do not look directly into the VFL output port. The laser light can cause eye damage.
- Use the device only as described in this manual.
- Keep the device away from water and high humidity.
- Do not attempt to disassemble or repair the device yourself. Contact qualified personnel for service.
- Ensure proper battery installation and replacement.
3. Product Overview
The QIIRUN TMOFI-401 combines a Live Fiber Optical Identifier (OFI) and a Visual Fault Locator (VFL) into a single, ergonomic unit. It is capable of identifying signal types (270Hz, 1KHz, 2KHz) and detecting optical power without disrupting traffic. The integrated VFL helps locate breaks and bends in fiber optic cables.

Figure 3.1: Front view of the QIIRUN TMOFI-401 with a fiber inserted.
Key Features:
- Identifies signal types: 270Hz, 1KHz, and 2KHz.
- Wide wavelength response: 800nm-1700nm.
- Supports various fiber sizes: 0.25mm, 0.9mm, 3.0mm.
- Built-in Visual Fault Locator (VFL).
- One-key operation, no need to replace clamp blocks.
- Low battery monitoring function.
- Ergonomic and lightweight design.
4. Package Contents
Verify that all items are present in the package:
- QIIRUN TMOFI-401 Optical Identifier with VFL
- Carry Case
- User Manual (this document)
- (Batteries not typically included, please check packaging)

Figure 4.1: Illustration of typical package contents including the device, carry case, and manual.
5. Device Layout and Controls

Figure 5.1: Detailed view of the device's display and control buttons.
- Fiber Groove: Area where the optical fiber is placed for identification.
- Direction Indicator: Arrows on the LED display indicating signal direction.
- LED Display: Shows relative core power, signal frequency (270Hz, 1KHz, 2KHz), and other status indicators.
- Frequency Indicator: LEDs for 270Hz, 1KHz, 2KHz.
- ON/OFF Button: Powers the device on or off.
- LOW BATT Indicator: LED that flashes when battery power is low.
- GLINT Button: Activates the Visual Fault Locator (VFL) function.
- Visible Laser Source (VFL Port): Output port for the red laser light.

Figure 5.2: View of the Visual Fault Locator (VFL) port with its protective cap removed.
6. Setup
6.1 Battery Installation
- Locate the battery compartment on the back of the device.
- Open the battery compartment cover.
- Insert two AAA batteries, ensuring correct polarity (+/-).
- Close the battery compartment cover securely.
6.2 Powering On/Off
- Press the ON/OFF button to power on the device. The LED display will illuminate.
- Press and hold the ON/OFF button for a few seconds to power off the device.
7. Operating Instructions
7.1 Using the Live Fiber Optical Identifier (OFI)
The OFI function allows for non-intrusive identification of optical signals.
- Ensure the device is powered on.
- Gently place the optical fiber into the fiber groove. The device is designed to accommodate 0.25mm, 0.9mm, and 3.0mm fibers without needing to change clamp blocks.
- The LED display will show the relative core power.
- If a modulated signal is present, the corresponding frequency indicator (270Hz, 1KHz, or 2KHz) will light up.
- The direction indicators (arrows) on the display will show the direction of the optical signal.
- Remove the fiber from the groove after identification.

Figure 7.1: Demonstrating the placement of an optical fiber into the identifier's groove.
7.2 Using the Visual Fault Locator (VFL)
The VFL emits a red laser light to visually locate breaks, bends, and poor connections in optical fibers.
- Ensure the device is powered on.
- Remove the protective cap from the Visible Laser Source (VFL) port.
- Connect the fiber to be tested to the VFL port.
- Press the GLINT button to activate the VFL. The red laser light will be emitted.
- Observe the fiber for any visible light leakage, which indicates a fault.
- Press the GLINT button again to turn off the VFL.
- Replace the protective cap on the VFL port after use.
Warning: Never look directly into the VFL output port or directly at the laser beam. Laser radiation can cause severe eye injury.
8. Maintenance
8.1 Cleaning
- Keep the device clean and free from dust and debris.
- Use a soft, dry cloth to wipe the exterior of the device.
- For the VFL port, use a lint-free swab and optical cleaning solution if necessary, ensuring no residue is left.
8.2 Battery Replacement
When the LOW BATT indicator flashes, replace the batteries promptly to ensure accurate operation. Refer to Section 6.1 for battery installation instructions.
8.3 Storage
When not in use, store the device in its carry case in a cool, dry place, away from direct sunlight and extreme temperatures.
9. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Device does not power on. | Dead or incorrectly installed batteries. | Replace batteries, ensuring correct polarity. |
| No reading on OFI display. | No optical signal; fiber not properly seated; dirty fiber/groove. | Verify signal presence; re-seat fiber; clean fiber and groove. |
| VFL laser is dim or not working. | Low battery; dirty VFL port; VFL module fault. | Replace batteries; clean VFL port; contact support if issue persists. |
| Inaccurate OFI readings. | Dirty fiber or groove; external light interference. | Clean fiber and groove; operate in a controlled lighting environment. |
10. Specifications
| Parameter | Value |
|---|---|
| Identified Signal Type | 270Hz, 1KHz, 2KHz |
| Wavelength Response | 800nm-1700nm |
| Applicable Optical Fiber | 0.25mm, 0.9mm, 3.0mm |
| Power Source | 2 x AAA Batteries (1.5V each) |
| Dimensions (L x W x H) | 230 x 43 x 36 mm (9.06 x 1.69 x 1.42 inches) |
| Weight | Approx. 200 g (0.44 lbs) |
| Color | Black |
| Manufacturer | TLDZ |
| Model Number | QIIRUN TMOFI-401 |
11. Warranty and Support
This product comes with a standard manufacturer's warranty. For specific warranty terms and conditions, please refer to the documentation provided with your purchase or contact your retailer. For technical support or service inquiries, please contact QIIRUN customer service through their official channels.
An optional 1-year extended warranty plan may be available for purchase separately. Please check with your vendor for details.