The L9219 requires a 5 V power supply and single battery to operate. This device offers forward and reverse battery operation. The rate of battery reversal may be ramped to meet international requirements. Additionally, a low-power scan mode, wherein all circuitry except the off-hook supervision is shut down to conserve power, is available. The dc current limit may be programmed via a single external resistor. Via the logic table, the current limit may be increased a nominal 42% above the value set by the IPROG resistor, giving the user a high-low current limit option.