Serial communication
Serial communication (RS-232, RS-422, RS-485) is the backbone of many OT systems where simple point-to-point or multidrop data transfer is sufficient.
The standards offer different benefits depending on needs:
- RS-232 Typically used for short distances (up to approx. 15 m), ideal for direct connection between one sensor or PLC and a PC
- RS-422 and RS-485 Supports longer distance and multi-device setups - RS-485, for example, allows up to 32 devices on the same bus over hundreds of meters and is tolerant to electrical noise
Areas of application
Suitable for connecting older machines and modular systems that only have serial interfaces to modern OT infrastructure.
For setup as a standalone control connection - e.g. between PLC and motor controller or HMI panel.
In multi-unit installations where the RS-485 bus is used to connect multiple sensors or actuators over longer distances.
Media converters in serial communication
Serial to serial devices
Converts the signal type between RS standards (e.g. RS 232 to RS 485) and resolves compatibility issues
Serial to fiber converters
Enables longer transport distances and immunity to electromagnetic interference - ideal for industrial environments
These technologies ensure robust and cost-effective connectivity in environments with both legacy and new OT devices, and can be easily integrated into existing infrastructures without advanced setup.
See a small selection of products for serial communication here
NPort 5100A serial device server, Moxa
NPort 5100A makes RS-232/422/485 serial devices network-ready via Ethernet in a simple and energy-efficient way.
Advantages:
- 1× RS-232/422/485 serial port
- 10/100 Mbps Ethernet
- Very low power consumption (<1 W)
- Built-in surge protection
- Supports Windows, Linux and macOS
- Item no.: 54947
NPort 5000AI-M12 serial device server, Moxa
The NPort 5000AI-M12 is a robust serial device server that connects RS-232/422/485 equipment to Ethernet in rail and transportation applications.
Advantages:
- 1/2/4 RS-232/422/485 serial ports
- EN 50155 and EN 50121-4 certified
- M12 Ethernet and power connector
- 2 kV isolation on serial signals
- 12-48 VDC power supply
- Item no.: 46579
NPort 6100-G2/6200-G2 series secure serial device servers, Moxa
The NPort 6100-G2/6200-G2 series are secure industrial serial device servers that enable reliable and encrypted connection of RS-232/422/485 equipment to Ethernet networks. Developed according to IEC 62443 requirements, the series is suitable for industrial and infrastructure applications with high security requirements.
Advantages:
- 1 or 2 x RS-232/422/485 serial ports
- Supports TLS and SSH with strong encryption (up to RSA-4096/ECC-521)
- Secure Boot and IEC 62443-4-2 compliant design
- 1 x 10/100Base-T(X) Ethernet port
- Operating temperature up to -40 to +75 °C (T models)
- Item no.: 55468