The card using a built-in voice-recognition chip requires users to give a spoken password that it recognizes. The idea is to prevent thieves from using a stolen card to buy goods online.  A model built by engineers in California packs a microphone, a loudspeaker, a battery and a voice-recognition chip into a standard-sized credit card. The card is the length and width of an ordinary credit card but about three times as thick. The company now plans to make it thinner.  The voice card is based on an earlier Beep card technology designed to prevent fraud in online deals. The Beep card has no microphone, but has a built-in loudspeaker to utter an audible   ID signal by a computer's microphone to an online server . By confirming that signal matches the information in the card, the server can make sure that the user is not simply keying in a credit card number but actually has the card in his hand. The ID code, which only the server knows, changes each time the card is used.  This prevents fraudsters recording the beeps, noting the card details and then playing back the audible ID when they key in the details later. But this earlier Beep card technology cannot prevent illegal use of stolen cards. The new voice card can. The new voice card doesn't identify itself by its ID until it has confirmed the real user's spoken password. Thieves will be unable to use the card because even if they knew the password they would have to be able to copy the owner's voice with a high degree of accuracy. The challenge for Beep card has been to develop voice-recognition and audio circuitry .  The voice-recognition credit is powered by a mini battery. To extend batter life, the electronics have only to be switched on when the card is being used. Pressing a button on the card's surface allows one to hear a female voice saying, "Say your password." If the voice-recognition software proves that the password is real, it sends its ID, which the server then identifies, allowing the deal to continue. What is the problem with the model card?
It is too large. It is too thick. It can't be used online. It has no loudspeaker.