Serial communication using 20mA/TTY interfaces continues to play a crucial role in industrial automation. The Com-Server 20mA from Wiesemann & Theis connects this proven technology with modern TCP/IP network communication, enabling classic serial systems to be securely and efficiently integrated into Ethernet-based networks. Designed to meet industrial requirements, it combines galvanic isolation, Power-over-Ethernet, and TLS encryption to ensure the highest reliability for Industry 4.0 and automation applications.

With comprehensive network services including Modbus/TCP gateway, FTP client/server, box-to-box communication, and support for virtual COM ports, the Com-Server 20mA provides a versatile platform for secure data exchange between 20mA devices and IP networks.

Integration of serial 20mA/TTY devices

The Com-Server 20mA enables seamless connection of serial 20mA devices to modern network environments. Proven COM port redirection allows serial applications under Windows to operate via virtual COM ports without any software modification. This ensures compatibility with legacy control programs – even in virtualized environments or systems without physical COM ports.

Optional TLS-PSK encryption secures communication between serial devices and Ethernet networks, which is essential for protecting data confidentiality in industrial control systems. Additionally, multipoint mode allows data to be distributed simultaneously to up to six network clients – for example, to measurement systems or control centers.

Box-to-box – serial communication via IP

Using the box-to-box function, two Com-Server 20mA units can be linked to create a virtual serial connection over Ethernet. This bidirectional and OS-independent setup replaces physical point-to-point wiring with a reliable network-based serial channel. If the connection is temporarily interrupted, automatic reconnect functions ensure seamless communication recovery.

This technology allows 20mA devices located far apart to communicate without dedicated cabling – ideal for cross-process automation and distributed measurement systems.

TCP/UDP socket communication

The Com-Server 20mA supports multiple communication protocols for maximum integration flexibility:

• TCP server: accepts incoming connections and forwards data directly to the serial interface.
• TCP client: actively connects to a defined host to send or receive data.
• UDP mode: suitable for latency-critical applications such as real-time measurement or control signal transmission.

Optional TLS encryption can be applied to any TCP-based communication, ensuring even sensitive process data is transferred securely – a major advantage in safety-critical production environments.

Modbus/TCP gateway for industrial integration

Acting as a Modbus/TCP gateway, the Com-Server 20mA enables classic Modbus/RTU devices such as energy meters or measurement converters to be integrated into Ethernet-based Modbus/TCP networks. Protocol conversion takes place directly within the device, eliminating the need for external converters – reducing costs and installation time.

This gateway functionality allows gradual modernization of existing serial infrastructures – a key step toward fully connected Industry 4.0 systems.

FTP client/server for data management

The integrated FTP client and FTP server provide flexible options for storing, archiving, and transferring serial data. Measurement results, event logs, or device status messages can be automatically uploaded to central FTP servers or stored locally.

Access is platform-independent and works with standard tools, making it ideal for data loggers, weighing systems, barcode scanners, or control platforms that require periodic documentation of output data.

Galvanic isolation and industrial-grade interfaces

The Com-Server 20mA is specifically designed for industrial environments. Its galvanically isolated 20mA/TTY interface prevents voltage surges and interference, ensuring reliable operation even in electromagnetically noisy conditions. The integrated Ethernet interface (10/100BaseT) supports autosensing and auto-MDIX for simplified network setup.

The device can be powered via Power-over-Ethernet (PoE) or externally with 12–48V DC through a screw terminal. With its rugged industrial design and optional DIN rail mounting, the Com-Server 20mA is well suited for use in control panels, cabinets, and machinery.

Easy commissioning with WuTility

Setup is straightforward using the free WuTility software. Within a few clicks, the device is detected on the network and can be configured via its integrated web interface. This interface allows parameter adjustments and management of box-to-box links, COM port profiles, and Modbus functions.

Professional users can also configure the device via Telnet or control sockets. DHCP support and remote management complete the administration concept.

Areas of application

• Industrial automation: integration of 20mA/TTY controllers and measurement systems into TCP/IP-based control environments.
• Process control: connecting distant 20mA sensors via box-to-box communication.
• Data archiving: recording and centralized storage of serial data via FTP.
• IoT networking: connecting analog measuring devices to digital data networks.
• Legacy compatibility: modernization of existing devices that rely solely on 20mA interfaces.

EMC compliance and industrial durability

The hardware complies with key industrial and EMC standards: EN 61000-6-2 (immunity) and EN 55032:2015 + A1 Class B (emissions). This ensures suitability for demanding production environments and continuous operation.

High reliability and long service life

Wiesemann & Theis provides a five-year warranty for the Com-Server 20mA. Its robust, low-maintenance design and 24/7 operational capability guarantee long-term stable performance. Galvanic isolation of signal paths further protects sensitive electronics.

Connecting classic 20mA technology to modern Ethernet networks

The Wiesemann & Theis Com-Server 20mA brings serial interfaces into the modern IP network world — secure, reliable, and industrial-grade. With Modbus/TCP gateway functionality, FTP data transfer, box-to-box links, and TLS encryption, it provides a powerful platform for integrating TTY systems into Industry 4.0 architectures.

Whether for continuous operation in production, transferring measurement data, or remote communication between controllers – the Com-Server 20mA is the ideal solution for making existing serial infrastructures future-ready.