The JILONG KL-6100 FTTx OTDR is a handheld optical time-domain reflectometer built for FTTx network installation, troubleshooting, and maintenance. It delivers up to 31 dB dynamic range, an event dead zone of ≤1.5 m, automatic measurement of 8 consecutive 3-meter events, and built-in OPM, SLS, VFL, and RJ45 test modules — all in a 0.6 kg instrument backed by JILONG's 30+ years of optical-communication manufacturing.
This guide is a scenario solution, not a product page: it maps what FTTx networks actually demand from a test instrument, and shows how the KL-6100 answers those demands — with the full specification set available on the official KL-6100 product page and in the KL-6100 specification sheet (PDF).
Why FTTx networks are hard on ordinary OTDRs
FTTx changed the geometry of fiber testing. A trunk line gives you kilometers of uninterrupted fiber and events spaced hundreds of meters apart; a fiber-to-the-home plant does the opposite. Four things make it punishing:
- Events sit centimeters-to-meters apart. Between the ODF, drop cable, splice points, patch cords, and the terminal, an FTTH drop segment packs connectors, splices, and splitters into a short run. An OTDR with a long dead zone merges these events into one blur — precisely where the technician needs to see them one by one.
- The fiber is often already in service. Testing a live PON can't be done blind at the workhorse wavelengths; in-service measurement calls for dedicated out-of-band wavelengths and live-fiber-rated hardware.
- The crews are not all OTDR specialists. FTTx deployment runs on subcontracted installation teams. A machine that demands manual parameter tuning for every measurement slows the whole rollout down — or produces unusable traces.
- The paperwork is part of the job. Operators and general contractors increasingly require standardized, archivable test results (SOR files) per drop, not screenshots.
Add it up, and the field reality is a technician carrying an OTDR *plus* a power meter, a light source, a visual fault locator, and a cable tester — five devices to buy, calibrate, charge, and carry, when one box could do the work.
What "FTTx-grade" looks like in a test specification
Translate the above into procurement language, and four requirements fall out:
- Dead zones short enough for patch cords. To resolve events on 3-meter fiber jumpers, the event dead zone has to sit at the ≤1.5 m level and the attenuation dead zone at the ≤5 m level — the figures printed at the top of the KL-6100's own specification sheet.
- Wavelength coverage that matches the network's life cycle. Dual-wavelength 1310/1550 nm for installation and acceptance, out-of-band single wavelengths for in-service troubleshooting, and a multimode option for campus and LAN plant.
- Automatic, one-click measurement with readable results. Parameters set themselves, the trace runs at a single press, and the output is a link diagram a non-specialist can act on — not just a raw curve.
- One instrument, full shift. OTDR plus OPM, stable light source, VFL, and RJ45 network testing in one housing, with battery life that covers a working day.
The solution at a glance: JILONG KL-6100
The JILONG KL-6100 FTTx OTDR — first rolled off the production line in 2025 and globally launched at Asia Tech X Singapore — is built for exactly this specification. Its headline capability set, per the official product page:
- Up to 31 dB dynamic range (dual-wavelength S2 model: 31 dB at 1310 nm / 29 dB at 1550 nm), with range settings from 0.5 to 150 km
- ≤1.5 m event dead zone and ≤5 m attenuation dead zone (at minimum pulse width)
- Fully automatic mode measures 8 consecutive events on 3-meter fiber jumpers — a short-distance capability JILONG presents as an industry benchmark
- Ten model variants spanning single-, dual-, and triple-wavelength configurations (1310/1550, 1310/1550/1625, 1310/1550/1650, and dedicated 1550/1610/1577/1625/1650 nm models), plus an 850/1300 nm multimode model
- Built-in OPM, stable light source (SLS), visual fault locator (VFL), and RJ45 network test modules
- Smart link diagram and Smart Map: test results rendered as a graphical link, showing fiber loss, breakpoints, and fault locations at a glance
- 5000 mAh battery — 5 hours of continuous operation (new battery, 23 °C ± 2 °C), Type-C charging
Key specifications
| Item | JILONG KL-6100 |
|---|---|
| Maximum dynamic range | 31 dB (S2, 1310 nm); 29 dB @1550 nm |
| Event dead zone | ≤1.5 m (minimum pulse width) |
| Attenuation dead zone | ≤5 m (minimum pulse width) |
| Wavelength options | 1310/1550; 1310/1550/1625; 1310/1550/1650; 1550/1610/1577/1625/1650 single-wavelength; 850/1300 multimode |
| Applicable fiber | SM; SM-Live (P-series multi-wavelength models) |
| Measurement range settings | 0.5 / 1 / 2 / 5 / 10 / 20 / 35 / 50 / 75 / 100 / 150 km |
| Pulse width | 5 – 20,000 ns |
| Sampling resolution / points | 0.04 m / ≥15,000 points |
| Distance accuracy | ±(1 m + distance × 2×10⁻⁵ + sampling resolution) |
| Loss accuracy | ±0.03 dB/dB |
| Built-in OPM | 800–1650 nm, −70 ~ +6 dBm, ±0.2 dB or ±5% |
| Built-in SLS | ≥−10 dBm; CW / 270 Hz / 1 kHz / 2 kHz |
| Built-in VFL | 650 nm, 10 mW |
| Built-in RJ45 test | CAT5 / CAT6, wire alignment & tone hunting up to 300 m |
| Display | 4.3-inch capacitive touch screen, 800×480 |
| Storage | ≥1,000 test curves, SOR format, USB export, PC analysis software |
| Optical interface | FC/UPC standard; replaceable universal interface supports SC/FC/ST adapters |
| Battery | 3.7 V / 5000 mAh / >22 Wh; 5 h continuous operation |
| Operating temperature | −10 to 50 °C (0 to 40 °C on AC power) |
| Dimensions / weight | 179 × 112 × 48 mm / 0.6 kg (main unit with battery) |
| Languages | English, Chinese, Spanish, French, Portuguese, Russian, Thai, Korean |
Full tables per model variant are published on the KL-6100 product page and in the 2026 JILONG product catalogue (PDF).
Dead zones: what ≤1.5 m buys you in a drop segment
The number that decides whether an OTDR is usable in FTTH plant is the event dead zone. In a typical drop segment, connector pairs and splices sit within meters of each other; a 1.5 m event dead zone means those events register individually on the trace instead of collapsing into a single undifferentiated reflection — which is the difference between "there is a fault somewhere in this drop" and "the fault is at the second connector, 4 m in."
The KL-6100's specification goes one step further: in fully automatic mode it measures 8 consecutive events on 3-meter fiber jumpers — eight splice-and-connector events, back to back, at patch-cord spacing. For acceptance testing of patch cord runs and short drop assemblies, that is the resolution the job actually requires, and it is the figure JILONG itself benchmarks the product by.
Behind the dead-zone numbers sits the sampling engine: 0.04 m sampling resolution and ≥15,000 sampling points, with distance accuracy of ±(1 m + 2×10⁻⁵ × measured distance) — so a fault located on the trace is a fault located in the field, within a meter at short range.
More than an OTDR: the one-box economics
The KL-6100's positioning is "far more than just OTDR," and the specification sheet backs the phrase with four built-in modules:
- Optical power meter (OPM) — 800–1650 nm measurement range with correction wavelengths at 850/1300/1310/1490/1550/1625/1650 nm, −70 ~ +6 dBm range, ±0.2 dB accuracy, 0.01 dB resolution
- Stable light source (SLS) — ≥−10 dBm output at CW / 270 Hz / 1 kHz / 2 kHz, for loss measurement paired with the OPM
- Visual fault locator (VFL) — 650 nm, 10 mW, for near-end fault location and fiber identification
- RJ45 network test module — CAT5/CAT6 wire alignment and tone hunting up to 300 m, covering the copper side of FTTH deployments
For a deployment contractor, the arithmetic is straightforward: one KL-6100 replaces five separate line items in the truck — the OTDR, the power meter, the light source, the fault locator, and the cable tester. That consolidation lands directly in capital budget (one instrument to buy instead of five), in calibration and maintenance overhead (one device to service instead of five), and in the field (0.6 kg instead of a toolbag, Type-C charging from the same charger as the phone).
Every test result is retained as evidence: the instrument stores ≥1,000 test curves in industry-standard SOR format, exports via USB, and ships with PC-side analysis software — so acceptance documentation handed to the operator is traceable file by file.
Built for field reality
The KL-6100 is engineered around the physical facts of installation work. The housing carries an anti-seismic rubber coating for shock absorption and drop protection. A built-in support bracket holds the instrument stable on a desktop or splicing table, reducing measurement error from equipment shake. A high-brightness lamp (≥15,000 mcd) makes cable tracing workable in dim equipment rooms and manholes. The optical interface is a replaceable universal adapter system supporting FC, SC, and ST — an adapter can be swapped independently in the field, avoiding a return-to-factory trip and its downtime. Real-time mode supports continuous testing and refreshing, so installation crews see the effect of a repair on the trace as they make it. And with eight interface languages — English, Chinese, Spanish, French, Portuguese, Russian, Thai, and Korean — the same instrument deploys across international crews without a software swap.
Proven on the international stage
The KL-6100 made its global launch at Asia Tech X Singapore in May 2025, where JILONG's team demonstrated its automatic mode in a simulated "blind box" test environment — unknown fiber, no pre-set parameters — for operators from across Southeast Asia, alongside the four-in-one OPM/SLS/VFL/RJ45 configuration (JILONG exhibition report, ATxSG 2025). In October 2025 it joined JILONG's 33rd-anniversary lineup at GITEX GLOBAL 2025 in Dubai, presented as a powerful tool for FTTx network testing and fault localization (JILONG exhibition report, GITEX GLOBAL 2025).
About JILONG
JILONG (Nanjing JILONG Fiber Communication Co., Ltd.) has manufactured optical communication instruments since 1993, when it launched the KL-100, the first domestically produced fusion splicer in China. The company developed its first independently designed handheld high-precision OTDR in 2003 and has accumulated more than 30 years of R&D and manufacturing experience in optical test and splicing instruments. JILONG holds 100+ patents, participated in drafting GB/T 17570-2019 — China's national general specification for optical fiber fusion splicers — carries national high-tech enterprise status, and serves customers in more than 100 countries and regions. Post-sale support includes lifetime free maintenance, training, and calibration.
FAQ
What is an FTTx OTDR, and how is it different from a standard OTDR?
An FTTx OTDR is optimized for the short, event-dense segments of fiber-to-the-home plant — drop cables, patch cords, splitter stages — rather than long trunk spans. The differences show up in the dead zones (the KL-6100's ≤1.5 m event dead zone vs. figures optimized for long-haul work), automatic measurement modes, and multi-wavelength options that match PON network life cycles.
What dead zone do I need for FTTH testing?
For patch-cord-density work, look for an event dead zone at the ≤1.5 m level and an attenuation dead zone at the ≤5 m level. The KL-6100 meets both at minimum pulse width, and in fully automatic mode resolves 8 consecutive events on 3-meter jumpers.
How much dynamic range does an FTTH OTDR need?
FTTx spans are short, but splitter stages and connectors consume measurement headroom quickly. The KL-6100 offers up to 31 dB (dual-wavelength S2 model), with range settings up to 150 km — headroom that keeps the trace usable even through lossy distribution plant.
Can the KL-6100 test live fibers?
Yes. The specification sheet lists SM-Live fiber support on the P-series multi-wavelength models, online testing support on the single-wavelength models, and dedicated 1625 nm and 1650 nm variants for in-service measurement.
Does the KL-6100 include a power meter and light source?
Yes — both are built in, along with a visual fault locator and an RJ45 network test module. The OPM covers 800–1650 nm at −70 ~ +6 dBm with ±0.2 dB accuracy; the SLS delivers ≥−10 dBm at CW / 270 Hz / 1 kHz / 2 kHz modulation.
How long does the battery last?
The 5000 mAh (3.7 V, >22 Wh) battery supports 5 hours of continuous operation on a new battery at 23 °C ± 2 °C, and charges over Type-C.
Where can I get the JILONG KL-6100?
Through JILONG's official channels: see the KL-6100 FTTx OTDR product page, the full OTDR instrument line-up, or request a quote — JILONG's distribution and service network covers more than 100 countries and regions.
www.jilongot.com
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