An acoustic touch apparatus is provided that includes a substrate capable of propagating surface acoustic waves, such as Rayleigh-type or Love-type waves. The dialyzing system is adapted to determine a blood pressure from a dialysate pressure detected by a pressure transducer 28 at the time of temporary suspension of the ultrafiltration without use of a special line for measurement of pressure in the blood flow line and free from danger of blood leakage from the blood flow line. If the amount of errors exceeds the repair threshold, the mobile station treats the download attempt as having failed and may send a new request if download is still desired. Each wafer includes a plurality of contact terminals each arranged in the wafer. Individual solenoid status is sent to a graphical display where an operator views said display to diagnose failure modes.