Features: With 8 channels for RS485 communication, the R413D08 module is the perfect solution for your Modbus-RTU protocol and AT command needs. Under AT command, the maximum delay is 9999 seconds; Under MODBUS command, the maximum delay is 255 seconds. AT commands can be made via serial HyperTerminal (serial assistant) input; MODBUS commands can be made via serial HyperTerminal (serial assistant) OR ''Modbus Poll'' input; With RS485 and RS232TTL dualbus interface; 8pcs Output control pins, 5VTTL level, low level (default) / high level output Specifications: Item: RS485 Modbus DC: 5V / 6V 24V Optional Operating Current: 10-15MA Support: RTU protocol AT instruction Length: approx. 45mm/1.77in for Relay Switch Board PLC Control Note: Due to problems with lighting effects and shooting angles, there will be certain tolerances in the product, please understand. Please allow 0-1cm error due to manual measurement. Package includes: 1pc RS485 Modbus