Some new scams have surfaced among criminals with new and ever more sophisticated ways to defraud people using public telephones. With so much business being done on the road, as people collect e-mail and keep in touch with the home office, travelers must be extra vigilant. In one scheme, a thief at a remote location, using a laptop computer and other technology, makes a call to a public payphone at a busy airport. The bell on the phone has been disabled and, as the consumer picks up the handset to place a call, the thief sends a simulated dial tone to the phone, fooling the caller into thinking he has a real dial tone. As the unsuspecting caller enters his calling-card number into the keypad, the thief records the tones and uses another device to convert them into a valid card number. To ensure the phone isn't being electronically monitored from a remote location, pick up the handset and hang up, wait 15 seconds and then place your call. When using a public telephone, be aware of nearby windows where a thief could be watching and block the view of the keypad when dialing your calling-card number. Purchase your prepaid cards only from reputable companies, as some customers have discovered that cards with extremely low rates sometimes are limited to certain areas or don't work at all.