RS-485 Interfaces

This page lists RS-485 devices that connect to a PC, either by converting to RS-232, or via USB and other interface. RS-485 devices are use for both BACnet and Modbus networks. See for hardware details and installation methods for RS-485 devices.


RS-485 to Ethernet Interfaces

Moxa NPort 5130

Contemporary Control Systems, Inc.

Lantronix UDS1100

Control Solutions, Inc.

They sell the Babel Buster line of converters for converting among Modbus RTU, Modbus TCP, BACnet, LonWorks, SNMP, etc.

eze System, Inc.

They sell an Ethernet to Modbus adapter/controller as well as an EzeIO Metering kit that bundles a CCS Modbus WattNode meter and CT's with their device, which also offers GSM connectivity.

Miscellaneous Brands/Models

Virtual Ethernet COM Port Drivers

There are several programs available that make virtual COM ports. These can be used to get a Modbus signal converted back from Ethernet into a COM port so that Modbus software could access the packets as Modbus RTU.

RS-485 USB Interfaces

The following interfaces provide RS-485 through a USB connected device. These generally create a virtual COM port under Windows.

B&B Electronics: USPTL4

SerialComm: Model USB-485B

SerialGear: USB-COM-I

SerialGear: USB-COMi-M

Sealevel: SeaLINK+485I

Sealevel: SeaLINK+485

Quatech: QSU2-400

ICP DAS: I-7561

ICP DAS: I-7563


ByteRunners' Serial Gear Clones,+RS-422,+RS-485+Serial+Adapters+(Single+Port)

US Converters' USB to RS-485/422 Mini

US Converters' USB to RS-485/422 Converter

Moxa: UPort 1130

UPort 1130

RS-485 to RS-232 Converters

RS-232 to RS-485 conversion is tricky and not recommended for new applications. A terminated RS-485 bus requires 60mA of drive current, but port-powered RS-232 adapters cannot provide this much current, so unless the adapter is powered with an external supply, these will not work with terminated or heavily loaded buses. Some vendors of this type are listed below.

RS485 to WLAN Interfaces

See Also

Keywords: RS-485 adapter


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