The Blackberry Curve normally rings for 15 seconds before going to voice mail. If you want to increase the number of rings on your Blackberry Curve, you can to do so by changing some settings. One reason why you may want to increase the number of rings is because you want more time to reach your phone before it goes to voice mail as you may be in another room or have to dig your phone out of your purse.
Turn on your Blackberry Curve. Go to "Options > Voicemail > Access Number." Write down the number you see. This is your carrier's voicemail number.
Type "61*XXXXXXXXXXX30#" onto your Blackberry Curve's main page, but replace the "X's" with your carrier's voice mail number.
Hit the green phone icon on the left side of the phone to reprogram it to ring for 30 seconds. This is the maximum ring limit for most phone carriers. Your phone will now ring for 30 seconds instead of 15.
You can also call your carrier and ask them to change the length of rings.