What system are you referring to? I'm not sure what you mean.
You may be referring to the Continuous Glucose Monitoring System (CGMS). I am using the Dexcom CGMS and it is especially good for warning me when my BG is rising, or dropping, and it tells me how fast the change is occurring. That enables me to take action early and prevent many highs and lows. The CGM is difficult to learn to use. The manuals do not give anough information. I have talked with friends who have learned many tricks and they have given me tips that makes my CGM agree closely with my glucose meter most of the time.