| 摘要 |
<p>Disclosed is a method of accessing a public telephone network (104) from a computer (101) via a modem (103), wherein the computer sends a first control signal indicative of a command to dial a telephone number to the modem; and in response to the first control signal the modem dials the telephone number. According to the invention, a filter (102) detects the command to dial the telephone number in the first control signal. The filter further determines whether the telephone number corresponds to an authorised telephone number based on a list of predetermined telephone numbers, and sends the command to dial the telephone number to the modem, if the telephone number corresponds to an authorised telephone number; otherwise causing the modem not to dial the telephone number. Further disclosed are a filter device and a computer program for authorising modem dialling. <IMAGE></p> |
