You can set the number of rings: either Normal or Long. Normal gives 2 rings and then to Voicemail. Long lets it ring and ring at least 7 times before it goes to "Missed Call" message, but no voicemail! Here's how: from Menu>Settings and Tools>#9. Call settings> #8. DTMF Tones. On that menu the choice is NORMAL, or LONG. Choose Long if you don't want Voicemail to pick up. But you will not get Voicemail at all. Which is what I wanted.
DTMF=Dual Tones Multi-Frequency. My roommate helped me on this.