Modbus RTU speaks over RS-485 with bit-level timing and cyclic redundancy checks. Cloud platforms demand JSON over MQTT or HTTPS. An industrial 4G modem bridges this gap not by translating, but by encapsulating. The modem treats each RTU frame as a binary payload, wraps it with a transport header, and forwards it via UDP or TCP to a cloud broker. This preserves the original register values, function codes, and error-checking fields, ensuring that the cloud receives an authentic snapshot of the field device.