Real-world serial communication on half-duplex RS485 buses is bottlenecked not by raw bandwidth but by latency between query and response cycles. Using a 100-MCU system at 115200 baud as an example, the author shows how grouping multiple messages into single transmissions — inspired by Isaac Asimov's 1962 story 'My Son, the Physicist' — can dramatically reduce the number of round-trip delays. Key techniques include batching acknowledgements, combining sensor and error reports, and using sentinel messages to signal end-of-stream, making a 10Hz polling cycle feasible despite OS and driver-induced millisecond delays.
