I use the restful api for voice calls. I used this to call myself. When my phone rings, I don't connect and hang up. After about 20 seconds, I received another call from twilio.
curl 'https://api.twilio.com/2010-04-01/Accounts/AccountSid/Calls.json' -X POST --data-urlencode 'To=+1111111' --data-urlencode 'From=+22222' --data-urlencode 'Url=http://demo.twilio.com/docs/voice.xml' -u AccountSid:authToken
I hope that when I hang up for the first time, I won't receive a second call.