DAC Systems utilizes a very modern IVR architecture. It is based on Linux, uses a native Voice over IP telecommunications subsystem, has an on board SQL database, and is data driven. It is purpose built from the ground up for IVR. It is proven and tested. For example, stress testing for the base platform design is performed where calls are presented to the system at 100% load continuously for several days while data I/O is being performed with an external system. The largest practical single server limit for our IVR design is 1000 concurrent calls (for example using a HP DL560 and VMware VSphere with 4 IVR guests).