On Nomorobo Mobile, there are two settings: Identified or Blocked.
On 'Identified' mode, all robocalls will still ring through on your phone, but the caller id will show you that it is a robocall. You can still pick the call up if you'd like.
On 'Blocked (Sent to Voicemail)' mode, all robocalls will be sent directly to voicemail. Your phone will not ring at all.