The Bit Voltage menu displays in real time the voltage when communication is occurring on the bus. The differential voltage and bit voltage (+, – line with respect to COM) from a controller are shown on the display. Approximately every half second, a new voltage sample is taken from the bus and displayed. The voltage sample could be from any controller on the bus that is communicating at the time of the sample. Use the Bit Voltage mode for a quick look at the quality of the communications occurring on the bus. For acceptable Bit Voltage ranges, see Voltage Levels and the Voltage Table .