The HC55171 is backward compatible to the HC5517 with the added capability of driving 5 REN loads. The HC55171 is ideal for any modem or remote networking access application that requires plain old telephone service POTS, capability. The linear amplifier design allows a choice of Sinusoidal, Square wave or Trapezoidal ringing. The voltage feed architecture eliminates the need for a high current gain node achieving improved system noise immunity, an advantage in highly integrated systems.