²HART communications occur at a rate of 1200 bits per second, and it is this slow by design: this slow data rate avoids signal reflection problems that would occur in unterminated cables at higher speeds. For more insight into how and why this works, refer to the “transmission lines” section 5.10 beginning on page 847. An example of a “slow” process variable suitable for HART digital monitoring or control is the temperature of a large building or machine, where the sheer mass of the object makes temperature changes slow by nature, and therefore does not require a fast digital data channel to report that temperature.