Keep note, many of the users did not like the idea of using a converter without galvanic-isolation especially in an industrial environment. It’s straightforward to convert the RS-485 line to the unbalanced UART interface using a dedicated IC. The simplest solution (as the one discussed here) does have reasonable protection features but is not galvanically-isolated ⚠

USB to RS485 is known for its multi-drop characteristics, which means it can be used for connecting multiple RS485 devices in a two-wire network. USB to RS422 is often used for extending a RS232 wire by using a USB to RS422 adapter at each end of a RS232 wire. Transmission mode: point-to-multipoint (up to 32 nodes, it is recommended to use repeaters for 16 nodes or more). Likewise, in some cases when termination is enabled, unexpected zero bytes can be received at the beginning or end of a message. To resolve this, bias resistors are often added to the Data+ (A) and Data- (B) lines to ensure that the lines go to an idle state when no node is driving data onto the bus. At this point, remember, only one set of bias resistors should only be used on the bus. So, the bias resistors should be removed from the module if another node on the bus is already providing the bias. Unfortunately, this module does not have jumpers for easy switching of the termination and bias resistors 😥 USB to RS-485 Converter – Isolation Thoughts

Manufacturer

DMXControl 3 http://wiki-en.dmxcontrol-projects.org/index.php?title=Getting_started_with_DMXControl_3

The USB to RS485 converter and USB RS422 adapter, otherwise referred to as USB to RS485/ USB RS422 converters, are small electronic devices used for converting USB signals into either RS485 or RS422. Some of these converter/ adapter units are limited to converting USB to either RS485 or USB to RS422 but others have the ability to convert both RS485 and RS422 via a built-in auto-detection function or other manual configuration selection. All units convert bi-directionally which means they all convert data signals in both directions. There are broad range of OEM companies that make these low cost converter devices that function to convert USB to RS485 and RS422 standards. RS485 and RS422 are communication standards that are suitable for harsh environments where there may be a lot of electrical interference from other devices and machines. These standards are half duplex transmission meaning that the only one communication is being done at a time using 2 wires. Using 4 wires full duplex can be achieved. Quality Guarantee - SerialComm converters are low priced, high quality products and made to last a lifetime. They are manufactured in a ISO-9001 certified facility using surface mount technology with lead free components. All converters are pretested prior to shipment and are fully guaranteed for 5 years. There are no converters, Commercial or Industrial that surpass SerialComm's quality standards at any price tag. The USB to RS485 converter and USB RS422 adapter are made in a variety of models and designs. The standard USB RS485 converter / USB to RS422 adapter is a non-isolated adapter which is used for many businesses, offices and personal devices. The isolated USB to RS485 converter / USB to RS422 adapter is used in many industrial and business environments as they are built to be resistant to moderate voltage spikes.This is an industrial USB to RS485 converter with original FT232RL inside. It features embedded protection circuits such as lightning-proof, resettable fuse, ESD protection, and TVS diode, etc. It's pretty small in size. USB cable problem: Using a poor-quality USB cable or USB plug may cause distortion or interference with the electrical signal, which may lead to automatic disconnection. Use good quality USB cables or USB plugs whenever possible.