Mike, esc telemetry follows a communications protocol and that is why ESCs capable of telemetry are connected to a UART on the controller. In the case of the hobbywing (based on what I am reading in the wiki) it does not provide telemetry in the manner that I described above. Instead it is just pulling the voltage high and low for each commutator similar to a Hall effect sensor. So it is really just an analog voltage going between 0 and 5 volts to indicate passing of a commutator. The RPM is calculated based on the time between the edges of the rising or falling voltage