USB 16 Relay Board PCB - ModBus RTU, Timers - Denkovi A E LTD
Amazon.com: WITMOTION USB to RS485 Modbus RTU UART Converter Cable with CH340 Chip, Terminated by 4 Way Female Socket Header, Serial Adapter (1m/3.28ft, Black), Windows 10,8,7, Linux MAC OS : Electronics
USB Temperature and Humidity Sensor MODBUS RTU Transmitter Industrial Port Probe | eBay
Modbus RTU Digital I/O over RS485/USB – Atac Technology Co., Ltd.