## Common ground
All options are devices that measure, record, or indicate the passage of time.
## Options at a glance
**8542.39 – RTC Module (IC)**
- **Defining trait:** A standalone integrated circuit chip designed to keep time in electronic systems.
- **Typical examples:** Real-time clock chips in computers, smartwatches, or embedded devices.
- **Best fit when:** The product is a small, internal component used for timekeeping in electronics.
**8543.70 – Employee Time Clock (Touchscreen)**
- **Defining trait:** A networked device for tracking employee work hours via biometric or PIN input.
- **Typical examples:** Modern HR time clocks with facial recognition or RFID readers.
- **Best fit when:** The product is used in workplaces to log attendance and manage labor time.
**9106.10 – Time-Register (Mechanical/Synchronous)**
- **Defining trait:** A mechanical or motor-driven device that records time intervals, often with a dial or paper roll.
- **Typical examples:** Industrial time clocks with rotating dials or paper tape.
- **Best fit when:** The product uses a physical clock movement or synchronous motor to record time.
**9503.00 – Time Clock Toy**
- **Defining trait:** A toy designed to teach children how to read and understand time.
- **Typical examples:** Plastic clocks with moving hands for kids’ learning.
- **Best fit when:** The product is marketed as an educational or play item.
## Key differences
| Feature | 8542.39 (IC) | 8543.70 (Employee Clock) | 9106.10 (Mechanical Register) | 9503.00 (Toy) |
|-----------------------|--------------------|----------------------------|---------------------------------|-------------------|
| Primary function | Internal timekeeping | Employee attendance | Record time intervals | Teach time |
| Technology | Integrated circuit | Touchscreen, biometrics | Motor or gear movement | Plastic, simple |
| User type | Developer/Engineer | Employer/HR | Factory worker | Child |
## How to choose
- Is it a small electronic chip inside another device? → 8542.39
- Is it used for tracking employee work hours with PIN, badge, or face scan? → 8543.70
- Does it use a mechanical movement or motor to record time on paper or dial? → 9106.10
- Is it designed for children to learn how to tell time? → 9503.00
## Overlaps & pitfalls
- A toy clock with a real-time chip (e.g., smart learning clock) could fit both 8542.39 and 9503.00.
- A mechanical time clock used in a factory might resemble 9106.10 but could be mistaken for 8543.70 if it has digital features.
- **No clear priority:** The main function determines the correct classification. If the product’s primary purpose is teaching time, use 9503.00; if tracking attendance, use 8543.70