FiberLert™ Live Fiber Detector


The easy, pocket-sized fiber troubleshooter

Quickly verify fiber activity, polarity, and connectivity with the FiberLert™ Live Fiber Detector. This pocket-sized tool tests single-mode, multimode, UPC and APC patch cords and ports with a non-contact / non-contaminating detector. The LightBeat™ feature flashes the LED, indicating a powered-on condition and good battery, a timer shuts FiberLert™ off after five minutes of inactivity to extend battery life (2xAAA, included). Rugged design includes a convenient pocket clip and is backed by a two-year warranty.

  • Detects optical power in single-mode and multimode fiber wavelengths (near infrared range 850 nm to 1625 nm)
  • No setup or interpretation needed – light and sound indicate presence of an optical signal
  • “Non contact” detector reduces the risk of contamination and damage
  • Suitable for ports and patch cords, SM, MM, UPC and APC connections
  • LightBeat™ flashes to indicate operation and battery status; powers off after five minutes of inactivity  to preserve battery life (2xAAA, included)
  • Two-year warranty

 

 

 

 

 

 

 

 

Applications

 

 

Check polarity and operation of patch cords.

 

 

Determine if a port is live. Small size makes it easy to access cramped patch panels.

 

 

Determine if a transceiver is operational. FiberLert can detect fiber signals without making contact.

 

 

 

Specifications

 

Feature Description
OPERATING PRINCIPLE Senses near infrared light emitted from fiber optic cabling. A continuous red glow at the handle and an audible beeping noise (if not switched off) indicates the presence of near infrared light.
OPTICAL INTERFACE Non-contact ceramic ferrule. Fits directly with 1.25 mm LC receptacles. Tethered ferrule adapter for testing 1.25 mm ferrule patch cord. Supports single-mode, multimode, UPC and APC connectors and ports.
WAVELENGTH DETECTION 850 nm to 1625 nm
OPTICAL POWER DETECTION RANGE +3 dBm to -30 dBm
LIGHT DETECTION Visible steady red LED indicator when optical power is detected
LIGHTBEAT™ INDICATOR Flashes twice every two seconds when unit is on and battery strength is sufficient.
BATTERY SAVER Unit automatically turns off after five minutes of inactivity
BATTERIES 2 AAA alkaline batteries included
BATTERY LIFE Typically, greater than 1 year (5 hrs. of use a week)
ITEM SIZE 0.6” x 1.0” x 6.6”  / 1.6 x 2.5 x 16.8 cm
ITEM WEIGHT 2.1 oz / 59 g
OPERATING TEMPERATURE RANGE -10 °C to 50 °C
OPERATING HUMIDITY RANGES 95 % (10 °C to 35 °C) Non-condensing 75 % (35 °C to 40 °C) Non-condensing uncontrolled < 10 °C
OPERATING ALTITUDE ≤ 3000 meters
STORAGE TEMEPERATURE -20 °C to 50 °C

Ordering Information

Model Description
FiberLert™-125  FIBERLERT, 850 NM TO 1625 NM LIGHT DETECTOR
FiberLert-125 6P  6 Pack - FIBERLERT, 850 NM TO 1625 NM LIGHT DETECTOR 

About Fluke Networks

Fluke Networks is the worldwide leader in certification, troubleshooting, and installation tools for professionals who install and maintain critical network cabling infrastructure. From installing the most advanced data centers to restoring service in the worst weather, our combination of legendary reliability and unmatched performance ensure jobs are done efficiently. The company’s flagship products include the innovative LinkWare™ Live, the world’s leading cloud-connected cable certification solution with over fourteen million results uploaded to date.

1-800-283-5853 (US & Canada)

1-425-446-5500 (International)

http://www.flukenetworks.com

Descriptions, information, and viability of the information contained in this document are subject to change without notice.

Revised: August 16, 2025 10:00 PM

Literature ID: 7004127

© Fluke Networks 2018