Description M5Stack Unit RS485-ISO is an isolated RS485 transceiver for converting TTL-level serial signals to RS485-level communication. Based on the RS485 bus protocol, it helps a host controller communicate with RS485 devices at the other end of a long-distance signal link. The unit uses a CA-IS3082W isolation chip to shield communication links from electrical noise and transient voltage or current changes. This isolation helps protect control equipment and reduce the risk of damage in industrial communication environments where signal-to-noise ratio and transmission distance matter. For interface conversion projects, M5Stack Unit RS485-ISO combines isolated DC-DC design, fail-safe receiver behavior, support for up to 256 bus nodes, and up to 1000 VRMS isolation withstand voltage. The isolated RS485 transceiver also supports signal transmission up to 500 Kbps, while the CA-IS3082W isolation chip provides the core isolation interface. Features M5Stack Unit RS485-ISO half-duplex interface unit based on the RS485 bus protocol. Isolated RS485 transceiver function for TTL-to-RS485 level conversion. CA-IS3082W isolation chip for shielding noise and transient changes. Integrated isolated DC-DC design. Signal transmission rate up to 500 Kbps. Fail-safe receiver behavior when the bus is open or shorted. Supports up to 256 bus nodes. Isolation withstand voltage up to 1000 VRMS. Development support for Arduino and UIFlow Blockly/Python. 2 x LEGO-compatible mounting holes. Specifications Withstand Voltage 1000V Maximum Nodes 256 ESD +/-15KV Protection Features Fail-safe, overcurrent protection, thermal shutdown protection Signal Transmission Rate Up to 500 Kbps Isolation Chip CA-IS3082W Product Size 56.0 x 24.0 x 10.2mm Product Weight 9.1g Package Size 138.0 x 93.0 x 11.2mm Gross Weight 17.8g Applications Communication between RS485 interface devices and microcontrollers in industrial equipment. Long-distance serial signal transmission using M5Stack Unit RS485-ISO. TTL-to-RS485 interface conversion with an isolated RS485 transceiver. Industrial control projects that benefit from the CA-IS3082W isolation chip and fail-safe protection. Product List 1 x Unit RS485-ISO 1 x VH-3.96 4p 1 x 120 ohm resistor 1 x HY2.0-4P Grove cable (20cm) 1 x I/O Sticker Other Content PORT.C UART pin mapping Black GND Red 5V Yellow UART_RX White UART_TX The receiving side is fail-safe: if the input is open or shorted, the receiver outputs a high level. For field devices, M5Stack Unit RS485-ISO is most useful where TTL logic must be connected to an RS485 bus while electrical noise and transients need isolation. In a multi-point setup, the isolated RS485 transceiver can support up to 256 bus nodes. The CA-IS3082W isolation chip and isolated power design help keep the controller side separated from the RS485 field side. Resources Unit RS485-ISO product document Unit RS485-ISO schematic PDF Unit RS485-ISO schematic image CA-IS3082W datasheet Unit RS485-ISO structure files Unit RS485-ISO Arduino example Unit RS485-ISO UIFlow example Unit RS485-ISO EasyLoader for M5Core Unit RS485-ISO PDF document FAQ What is Unit RS485-ISO used for? It is used to convert TTL-level serial communication to RS485-level communication for long-distance and industrial device links. Which isolation chip does it use? It uses the CA-IS3082W isolation chip as the interface chip. How many RS485 bus nodes can it support? The listed maximum node count is 256. What happens if the RS485 input is open or shorted? The fail-safe receiver outputs a high level when the input is open or shorted. What is included in the package? The package includes 1 x Unit RS485-ISO, 1 x VH-3.96 4p, 1 x 120 ohm resistor, 1 x HY2.0-4P Grove cable (20cm), and 1 x I/O Sticker. What development platforms are supported? The product information lists Arduino and UIFlow Blockly/Python development support for M5Stack Unit RS485-ISO. Why use an isolated RS485 transceiver? An isolated RS485 transceiver helps separate the controller side from noisy field wiring, which is useful when equipment needs more protection during RS485 communication.
