Extracting Inflation from Stock Returns to Test Purchasing Power Parity

A two-wire serial (TWS) bus allows bus mastering by any device on the bus utilizing pull-ups. The bus is actively driven low, but typically pulled high by pull-up resistors for each device on the bus. When some of the devices on such a bus have backup power, draining of backup power whenever primary power is lost is avoided by isolating the devices with backup power from the devices without backup power on the TWS bus.