Optical Fiber Identifier K-340

• Three instruments share this housing: the identifier reads live fiber, the built-in 10 mW visual fault locator (650 nm, 2.5 mm universal connector, 8–10 km reach) finds the break or the crushed bend the reading pointed at, and an LED work light covers the cabinet corners where both jobs happen in the dark
• No chucks to change: one universal multi-in-one fixture takes Ø0.25 bare fiber, Ø0.9, Ø2.0 and Ø3.0 cable as it comes — the swap-and-lose-a-chuck step disappears, and so does the pause while the right chuck is found at the bottom of a tool bag
• The display does the talking: relative power from -40 to +10 dBm and the recognised tone on a backlit LCD, direction on the arrow LEDs, and a NO SIGNAL indicator that says the fiber is dark without ambiguity — readable at arm's length, in a dark closure, without a headlamp
• Tone recognition at 270 Hz, 1 kHz and 2 kHz for end-to-end tracing: modulate the far end, then sweep the bundle until this one answers — identification and fault location in a single visit, on a circuit that never comes down
• Plastic housing, honestly specified: the lighter, lower-cost build (219 × 45 × 28 mm, 235 g) is the point of this model — two AA batteries power the identifier, the VFL and the light, so the belt kit stays one tool and one battery type
• Private labeling made to your requirements — labels with your logo, part numbers and barcodes on the inner boxes and outer cartons, ready for your warehouse

The identifier works like every macro-bend detector: the fiber sits in the universal fixture under a controlled bend, a fraction of the light escapes, and two Ø1 mm InGaAs detectors compare what leaks on each side — the stronger side is where the light comes from, which the arrows report. The reading on the LCD is the fiber's relative power, and the tone detector listens for the 270 Hz, 1 kHz or 2 kHz modulation a source at the far end would add.

The universal fixture is this model's working difference: instead of swapping chucks per coating, one holder geometry centres 0.25, 0.9, 2.0 and 3.0 mm fiber alike. On a tray of mixed cords — a 3.0 jumper here, a 0.9 pigtail there — the tool moves from fiber to fiber without a pause, which is exactly when identification gets done properly instead of sampled.

When the identifier says the fiber is live but wrong — weak, or dark past a point — the same tool switches jobs: the VFL button launches 10 mW of 650 nm red light into the fiber through the 2.5 mm universal connector, and the fault glows through the jacket at the break or the tight bend, visible across a dark cabinet. Identification located the circuit; the VFL locates the fault on it.

Field notes: the NO SIGNAL lamp is a result, not an error — it means the clamped fiber carries nothing the detectors can see. Keep the fixture faces clean, since the bend geometry is the measurement; and the LED light is for working, not for inspecting connector end-faces — that still wants a microscope.

• One K-340 optical fiber identifier
• Soft carry case