Detailed LRF1221C Specifications
The technical material below is retained for this model only. Do not transfer a range, pulse, interface, mechanical or safety value from another 1535 nm product.
TECHNICAL SPECIFICATIONS
| Project | Performance Indicators |
| Model | LRF1221C |
| Laser Wavelength | 1.54μm±0.02μm |
| Eye- safety | Class Ⅰ |
| Divergence Angle | ≤0.3 mrad |
| Laser Energy | ≥300 μJ |
| Launch Lens Diameter | Φ12 mm |
| Receiver Lens Diameter | Φ40 mm |
| Measuring Range
（Reflectance 30%; visibility ≥15km.） |
4m × 6m Objective ≥12 km |
| Minimum Range | ≤50 m |
| Ranging Frequency | 0.5Hz ~10Hz |
| Communication interface | RS422 |
| Ranging Accuracy | ±2 m |
| Range Resolution | ≤0.1 m |
| Precision Rate | ≥98% |
| False Alarm Rate | ≤1% |
| Pin-in-lead package model | J30J |
| Supply Voltage | DC12 V |
| Standby power consumption | ≤1.2W |
| Average power consumption | ≤2 W |
| Peak Power Consumption | ≤3W@10Hz |
| Weight | ≤275g |
| Dimension (L×W×H) | 107×62×72mm |
| Operating Temperature | -40～+70 ℃ |
| Storage Temperature | -55～+75 ℃ |
| Impact Resistance | Meet the MIL-STD-810G testing standard |
| Vibration Resistance | Meet the MIL-STD-810G testing standard |
OUTLINE DIMENSION(mm)
107×62×72mm
PIN INTERFACE
Selectable between TTL (Molex 51021-0500) / RS-422 (J30J)
1 Electrical connector model: Molex51021-0500. The detailed definition of the electrical interface is as follows:
Table 1 Interface definition
|
External plug-in XS3 |
Model：Molex51021-0500 |
Remark |
|
1 |
TTL RX |
3.3V |
|
2 |
TTL TX |
3.3V |
|
3 |
CTRL |
3.3V-5V power on, 0V power off |
|
4 |
+12V |
Power supply+ |
|
5 |
GND |
Power supply- |
2. Electrical connector model: J30J; The corresponding plug and cable shall be provided by Party B. The detailed definition of the electrical interface is shown in the following table:
Interface Definition
|
Pin |
Definition |
Function |
Remarks |
|
1 |
GND |
Serial Port Ground |
|
|
2 |
GND |
12V Input Negative |
|
|
3 |
GND |
12V Input Negative |
|
|
4 |
VCC 5V |
12V Input Positive |
|
|
5 |
VCC 5V |
12V Input Positive |
|
|
6 |
RS422 RX+ |
Serial Port Receive + |
From the upper computer to the rangefinder |
|
7 |
RS422 RX- |
Serial Port Receive - |
From the upper computer to the rangefinder |
|
8 |
RS422 TX- |
Serial Port Transmit - |
From the rangefinder to the upper computer |
|
9 |
RS422 TX+ |
Serial Port Transmit + |
From the rangefinder to the upper computer |
Model-specific conditions and limits
Conditions are retained only when the source states them. They are not reconstructed from a nominal range or wavelength.
Read the controlled model table for its stated target, reflectance, visibility, temperature, rate and acceptance conditions. No additional condition has been inferred for this model.
Pulsed Time-of-Flight Ranging
A pulsed rangefinder estimates one-way distance from the round-trip delay of an accepted optical return. The equation is general engineering context, not an additional LRF1221C specification.
Pulse energy describes emitted energy per pulse; its effect cannot be separated from pulse width, divergence, optical losses, receiver threshold and the stated target/atmosphere conditions. It is not a substitute for a model-specific near- or long-range acceptance test.
Source-stated application context
Application labels indicate evaluation context, not automatic fitness for a finished system.
Product Description
LRF1221C 12km 1535nm Eye-Safe Long-Range Laser Rangefinder Module for Border, Coastal and Mapping Systems
The LRF1221C is a 1535nm Class I eye-safe long-range laser rangefinder module engineered as an OEM core for border surveillance, coastal observation, reconnaissance, surveying and mapping systems. With no outer housing and multiple electrical interfaces, it is designed to be embedded directly into handheld devices, multifunction sights, vehicle and shipborne turrets, and fixed electro-optical stations, supported by PC host software and embedded firmware for rapid integration.
Using a 1.54µm±0.02µm erbium-glass laser, a ≤0.3 mrad divergence angle and ≥300µJ single-pulse energy, together with a Φ12 mm launch lens and Φ40 mm receiver lens, the LRF1221C delivers ultra-long-range performance. Under 30% reflectance and visibility ≥15km, it reaches ≥12 km on a 4m×6m objective, with a minimum range of ≤50 m. Ranging accuracy is ±2 m, resolution ≤0.1 m, precision rate ≥98% and false alarm rate ≤1%, giving system designers reliable distance measurements for wide-area border lines, coastlines and high-vantage mapping platforms.
The ranging frequency is adjustable from 0.5 Hz to 10 Hz, enabling both low-duty-cycle monitoring and higher refresh rates for tracking. Time-of-flight processing with up to three reported targets per shot allows first/main/last-target logic in layered scenes such as harbor approaches, coastal cliffs, mixed vegetation and built-up areas. This makes the LRF1221C suitable not only for classic distance measurement, but also for long-range situation awareness and target cueing in EO/IR and thermal imaging systems.
Electrically, the module operates from a DC 12 V supply. Standby power consumption is ≤1.2 W, average power ≤2 W and peak power ≤3 W @10 Hz, offering an efficient balance between 12km-class performance and power budget in tower, vehicle and shipborne installations. A Molex 51021-0500 connector exposes a TTL (3.3 V) interface with RX, TX, CTRL (3.3–5 V power on, 0 V power off), +12 V and GND, while a J30J pin-in-lead package provides an RS-422 differential interface with RX+/RX− and TX+/TX− pairs and redundant supply pins. Integrators can therefore select TTL for compact internal wiring or RS-422 for long cable runs in noisy environments.
Communication uses a master–slave protocol at 115200 bps, with 8 data bits, one start bit, one stop bit and no parity. The frame structure consists of a 0x55 header (STX0), command word (CMD), length byte (LEN), parameter bytes (DATAH/DATAL) and an XOR checksum (CHK). Core commands include standby (stop continuous ranging), single ranging, continuous ranging with a programmable period in milliseconds, self-test, distance selection and minimum range (blind-zone) setting, cumulative shot-count query, APD power on/off and serial-number query. Response frames return self-test voltages and temperatures, blind-zone values, total shot counts and up to three target distances (0.1 m resolution) along with a status flag byte that reports main-wave and echo presence, laser status, timeout, APD status and whether fore and aft targets are present.
Mechanically, the LRF1221C measures 107 × 62 × 72 mm and weighs ≤275 g, using a pin-in-lead J30J package for rugged mounting. It is specified for an operating temperature range of −40 to +70 °C, storage from −55 to +75 °C, and meets MIL-STD-810G impact and vibration test standards, ensuring long-term reliability on border towers, coastal headlands, armored vehicles, patrol craft and other platforms exposed to harsh weather and mechanical shock.
For systems requiring a protective optical window—such as sealed coastal stations, radar/EO fusion masts or hardened border sensors—the optical window should use an anti-reflective coating optimized for 1525–1545 nm with ≥99% transmittance. After additional hydrophobic or hard coatings and mechanical assembly, overall transmittance should remain ≥97%. Window thickness is typically controlled within 2–4 mm, the emission axis should be aligned within 2–4° of the window normal, and the air gap kept as small as possible, while the effective aperture and outer diameter follow the recommended geometry to limit absorption and back-reflection.
With its 12 km NATO-class range, eye-safe 1535nm wavelength, compact OEM form factor, selectable TTL/RS-422 interfaces and complete communication protocol, the LRF1221C is an excellent choice for border and coastal surveillance networks, long-range EO/IR and thermal imaging systems, reconnaissance and mapping payloads, fixed observation posts and industrial distance-measurement equipment that demand stable, long-range distance data and straightforward serial integration.
Confirm short- and long-distance acceptance conditions
- Define minimum distance, target material, reflectance, size and incidence angle.
- Check receiver recovery, optical-axis overlap and strong-return handling at the intended near limit.
- Verify supply tolerance, peak current, grounding, interface levels, connector and timing with the ordered revision.
- For long-distance acceptance, state target geometry, visibility, weather, background and required detection probability.
- Test with the installed window, boresight, field of view, enclosure and thermal path rather than a bare module alone.
- Evaluate accessible emission, labels and failure conditions again for the finished laser product under IEC 60825-1.
Questions to resolve before design release
Does a stated maximum range apply to every target?
No. A stated range must be read with its target and environmental conditions. Dark, small, oblique, wet or partially obscured targets and degraded visibility can reduce received signal.
Does 1535 nm itself establish the laser classification?
No. Classification concerns accessible emission from the finished laser product. The module statement and final instrument assessment are distinct.
Can a long-range claim be used as the minimum range?
No. Minimum-distance behaviour depends on the particular transmit/receive geometry, receiver timing and strong-return management documented for the model and host system.
Product evidence and general technical context
The model PDF controls model claims. Public references below explain general engineering principles only.
- ERDI LRF1221C model PDFModel-specific technical evidence.
- System Design of a Pulsed Laser RangefinderOptical Engineering 30(3), 1991 - link budget, background, noise, detection and range error.
- The Short-Range, High-Accuracy Compact Pulsed Laser Ranging SystemSensors 22(6), 2146, 2022 - pulsed-ToF equation, timing error, reflectivity and temperature effects.
- Laser system range calculations and the Lambert W functionApplied Optics 48(4), B1-B7, 2009 - range performance versus atmospheric transmission, target and system parameters, and threshold SNR; its 1.06 µm example is general context, not ERDI model data.
- Monostatic all-fiber rangefinder systemApplied Optics 54(25), 7687-7694, 2015 - a measured case study of shared-aperture geometry and receiver-recovery loss; it does not establish an ERDI model limit.
- Light Transmission in Fog: The Influence of Wavelength on the Extinction CoefficientApplied Sciences 9(14), 2843, 2019 - measured and modeled wavelength-dependent fog attenuation.
- IEC 60825-1:2014Laser-product classification and accessible-emission requirements; final equipment requires system-level assessment.
- Practical application of pulsed “eye-safe” microchip laser to laser rangefindersOpto-Electronics Review 21(3), 2013 - a peer-reviewed 1535 nm rangefinder implementation; use for general transmitter/receiver and atmospheric-design context, not model specifications.