Received calls both yesterday and today with caller ID showing this number with a Caller ID name of "SIOUX FALLS  SD".     I immediately disconnected the call yesterday and let the one today ring until the caller disconnected after 20+ rings (actually I didn't count, but I'm pretty sure there were that many).    Attempting to call the number results in a busy signal after a long silence so it's likely unassigned/faked/spoofed.  

Very likely that this is the Senior Medical Alert device extortion scam.    (They have used 605-413-1045, 605-413-1047, 605-413-1048, 605-413-1506, 605-413-1506, 605-413-4523 in the past along with several other SD numbers and hundreds of other area code numbers.)  

If so, don't fall for the medical alert device "paid for by a loved one"  nonsense or the promise of $3,000 in grocery coupons.   It may well cost you $1,000 to get nothing.