In mobile operation scenarios such as power line inspection, rail transit maintenance, outdoor construction, and scientific research exploration, tasks like on-site equipment commissioning, work logging, and data collection also have an urgent need for precise timing. Traditional fixed-time servers cannot meet the time‑synchronization requirements of mobile environments, while ordinary watches and smartphones offer relatively low time accuracy, making it difficult to ensure temporal consistency in operational data. In response to the time‑synchronization needs of mobile operation scenarios, Beijing Zhongxinchuang Technology Co., Ltd. has developed and launched The DNHH series of handheld mobile time‑keeping devices combines portability, high precision, and robust adaptability, providing a convenient and reliable solution for time synchronization in mobile environments. The core strength of the DNHH series lies in its seamless integration of a compact, portable design with highly accurate time dissemination. This product line includes models such as the DNHH‑9, DNHH‑9‑B, DNHH‑9‑R, and DNHH‑9‑GB. The units feature an ergonomically designed body, weighing approximately 500 grams and measuring roughly the size of a tablet, making them easy to hold and carry—ideal for extended outdoor operations. Each device is equipped with a high‑definition LCD display that offers clear, easy‑to‑read readings and includes a backlight function, ensuring optimal visibility even in low‑light or nighttime conditions and supporting all‑day use. In terms of timing performance, the DNHH series incorporates a high‑performance satellite‑based time‑synchronization module that supports signals from BeiDou, GPS, and other satellite systems. It can rapidly acquire and lock onto satellite signals to obtain precise standard time, achieving millisecond‑level accuracy to meet on‑site time‑verification and recording requirements. The devices are powered by a large‑capacity, rechargeable lithium battery that delivers over 12 hours of continuous operation on a single charge, with USB‑type fast charging to accommodate field‑use scenarios. Certain models also offer offline time‑keeping capabilities: in indoor or underground settings where satellite signals are blocked, they rely on an onboard clock chip to maintain time accuracy and automatically synchronize with standard time once satellite reception resumes. Regarding environmental resilience and durability, the DNHH series has been specially optimized. Its housing is constructed from high‑strength engineering plastics and rubberized, non‑slip materials, offering drop resistance, abrasion resistance, dust protection, and water resistance. The devices have passed a 1.5‑meter drop test and achieved IP54‑rated protection, enabling them to withstand the rigors of outdoor conditions—including bumps, sand, and rain. They operate across a wide temperature range of –20°C to +60°C, ensuring stable performance in extreme heat or cold, and are well suited to diverse applications such as power‑line inspections, outdoor construction, and scientific exploration. In terms of functionality, different models within the DNHH series offer tailored features to address specific use cases. Some models include data‑logging capabilities, allowing users to record operation times, device IDs, operator information, and more, with a storage capacity exceeding 100,000 entries; data can be exported via USB for easy traceability and management. Others support wireless synchronization, enabling remote time alignment with a backend server through 4G or Wi‑Fi, eliminating the need for manual on‑site adjustments. Additionally, select models are equipped with supplementary interfaces—such as RS‑232 and PPS—enabling direct time synchronization or verification with field equipment, thereby enhancing operational convenience and accuracy.

The DNHH series of handheld mobile time‑keeping devices has been widely deployed across numerous mobile‑work scenarios, yielding well‑established industry‑specific use cases. In the power sector, inspection personnel from State Grid, China Southern Power Grid, and other utilities employ these devices to conduct transmission‑line inspections and substation equipment maintenance, ensuring synchronized timing for inspection records and defect reporting, thereby enhancing the standardization and efficiency of field operations. In the rail transit industry, maintenance teams on lines such as the Hangzhou Metro and Beijing Metro utilize these devices for track‑equipment commissioning and signal‑system testing, guaranteeing temporal consistency in maintenance tasks and preventing coordination issues arising from timing discrepancies. In outdoor construction settings—ranging from road building to bridge construction—workers rely on these devices to document progress and collect data, ensuring the temporal accuracy of construction logs and supporting quality‑assurance traceability. In scientific research and exploration, geologists, meteorologists, and other researchers use these devices for field data collection and experimental recording, safeguarding the temporal consistency and reproducibility of their scientific datasets.

In addition, The DNHH series of handheld mobile time‑keeping devices can be integrated with the Zhongxin Chuang intelligent, network‑wide time‑synchronization monitoring software. Through the platform, administrators can view device location information (with GPS positioning supported on select models), operational status, and time‑synchronization status; they can also remotely configure device parameters and update firmware, facilitating centralized management and maintenance.