The PI-1A is only designed to work with a page port or a vacant trunk port, so your ATA would need to provide an FXO port to be compatible with the PI-1A.  If the ATA is only capable of supplying dial tone (FXS port), you would need a different product that is capable of auto answering the call from the FXS port.  We make other products that will work for that application like the RAD-1A or the FXI-1A.  To make sure you purchase the correct product, contact our help line at (715) 386-8861 and they can assist you.