This read-write enumeration sets the ring voltage, expressed in volts RMS such as 60 or 80, applied to locally attached equipment when generating a ring signal. An administrator selects this based on the ringer sensitivity of the connected phone equipment, since insufficient voltage may fail to ring a phone reliably. For example, older or long-loop telephone equipment might need the higher rms-Volts-80 setting to ring consistently compared to closer, modern equipment on rms-Volts-60.