The JMDM-RS232 serial control relay (transistor) board is an industrial‑grade controller developed by Jingmin Digital. It provides RS232 serial communication for controlling up to 12 relay or transistor channels and can monitor 16 digital input points.
The manual describes wiring, software setup, command formats, performance parameters, and application examples such as building automation, lighting control, and remote I/O modules. Contact information for the manufacturer is also included. This manual is written in Chinese.
| Relay/Transistor Channels | 12 |
|---|---|
| Digital Input Channels | 16 |
| Communication Interface | 1× RS232 (standard, 15 kV ESD protection) |
| Maximum Network Length | 1 km (via RS485 extension) |
| Output Voltage (Relay) | 0‑220 V |
| Maximum Output Current (Relay) | 5 A |
| LED Indicators | 2 |
| PCB Size | 155 mm × 110 mm |
| Addressable Controllers per RS232 | 255 |
It can independently control 12 relay or transistor channels.
The board provides a standard RS232 serial interface with 15 kV ESD protection.
The network can be extended up to one kilometre using RS485.
The controller can monitor the status of 16 digital input points.