Before revision: Infone identified a registered user (along with billing information ... the service was only payable by credit card) by caller ID (number were registered on signing up) and by an advanced voiceprint recognition system from SpeechWorks that identified the user when the user called from an un-registered telephone number (or no caller ID) through the use of a personal phrase spoken by the user (e.g., "Hello Infone!")
After revision: Infone identified a registered user (along with billing information ; the service was only payable by credit card) by caller ID (number were registered on signing up) and by an advanced voiceprint recognition system from SpeechWorks that identified the user when the user called from an un-registered telephone number (or no caller ID) through the use of a personal phrase spoken by the user (e.g., "Hello Infone!")