DC 12V RS232 Serial Time Delay Relay Board – DB9 1-Channel
DC 12V RS232 Serial Time Delay Relay Board – DB9 1-Channel
DC 12V 1-Channel RS232/UART Time Delay Relay Board with DB9 Serial Port
Take precise control of your automation projects with this compact DC 12V Single-Channel Time Delay Relay Board. Featuring a standard DB9 RS232 serial port, this relay module communicates via both AT commands and 8-byte UART instructions — automatically recognized without any manual switching. Whether you're building a home automation system, industrial control panel, or embedded electronics project, this board delivers reliable, programmable switching in a minimal footprint.
Key Features
- Dual Instruction Sets: Supports AT commands and 8-byte binary instructions with automatic protocol detection — no configuration needed.
- 6 Versatile Working Modes: Open, Close, Click (momentary), Self-locking, Interlocking, and Time Delay — covering virtually every switching scenario.
- Extended Delay Control: Under AT command mode, program delays of up to 9,999 seconds for precise timed automation.
- RS232 DB9 Connectivity: Standard DB9 serial connector makes integration with PCs, microcontrollers, and industrial equipment straightforward.
- High Load Capacity: Handles up to 10A at 250VAC / 30VDC, making it suitable for controlling lights, motors, solenoids, and more.
- Ultra-Low Standby Current: Only 16mA standby draw (47mA with relay energized) — efficient and ideal for always-on applications.
- Compact & Lightweight: Measures just 56.5 × 31.5 × 17.5 mm and weighs 24g — easy to integrate into tight enclosures.
Technical Specifications
| Working Voltage | DC 12V |
| Standby Current | 16mA |
| Active Current (1 relay open) | 47mA |
| Serial Interface | RS232 DB9 Port |
| Instruction Types | AT Command & 8-Byte Binary (auto-detected) |
| Working Modes | Open, Close, Click, Self-locking, Interlocking, Delay |
| Max Delay (AT Command) | 9,999 seconds |
| Max Load | 10A / 250VAC · 10A / 125VAC · 10A / 30VDC · 10A / 28VDC · 10A / 12VDC |
| Dimensions | 56.5 × 31.5 × 17.5 mm |
| Weight | 24g |
| Country of Origin | Made in China |
What's in the Box
- 1× DC 12V 1-Channel Time Delay Relay Board
Safety & Compliance
This board operates at low voltage (DC 12V) and falls within EU LVD low-voltage thresholds (below 50VAC / 75VDC). Always follow proper electrical safety practices when connecting relay outputs to mains voltage loads. For electrical safety guidelines, refer to OSHA Electrical Safety Standards.
Notes
- Due to monitor color settings, actual product color may vary slightly from images.
- Please allow ±1–3 cm variance due to manual measurement.
Frequently Asked Questions
Q: What serial communication protocols does this relay board support?
A: This relay board supports both AT commands and 8-byte binary UART instructions over an RS232 DB9 serial interface. The board automatically detects which protocol you're using — no manual switching or configuration is required, making it highly flexible for integration with PCs, PLCs, or microcontrollers.
Q: What is the maximum time delay this relay board can be programmed for?
A: When using AT command mode, the board supports a maximum programmable delay of 9,999 seconds (approximately 2.78 hours). Note that the 8-byte binary instruction mode does not include a delay mode, so use AT commands for timed switching applications.
Q: What loads can I safely connect to this relay board?
A: The onboard relay is rated for a maximum load of 10A at 250VAC, 10A at 30VDC, and several intermediate ratings. This makes it suitable for switching lights, small motors, solenoid valves, fans, and other resistive or inductive loads within these limits. Always follow appropriate electrical safety practices and use proper wiring for the connected load.
Q: What working modes are available on this relay board?
A: The board offers 6 working modes: Open (normally open), Close (normally closed), Click (momentary toggle), Self-locking (latching), Interlocking, and Time Delay. This versatility covers a wide range of automation and control use cases.