A dialer (US) or dialler (UK) is an electronic device that is connected to a telephone line to monitor the dialed numbers and alter them to seamlessly provide services that otherwise require lengthy access codes to be dialed. A dialer automatically inserts and modifies the numbers depending on the time of day, country or area code dialed, allowing the user to subscribe to the service providers who offer the best rates. For example, a dialer could be programmed to use one service provider for international calls and another for cellular calls. This process is known as prefix insertion or least cost routing. A line powered dialer does not need any external power but instead takes the power it needs from the telephone line.
Another type of dialer is a computer program which creates a connection to the Internet or another computer network over the analog telephone or Integrated Services Digital Network (ISDN) network. Many operating systems already contain such a program for connections through the Point-to-Point Protocol (PPP).
Many internet service providers offer installation-CDs to simplify the process of setting up a proper Internet connection. They either create an entry in the OS's dialer or install a separate dialer (as the AOL software does).
In recent days, the term "dialer" often refers specifically to dialers that connect without the user's full knowledge as to cost, with the creator of the dialer intending to commit fraud.
The cost of setting up such a service is relatively low, amounting to a few thousand dollars for telecommunications equipment, whereupon the unscrupulous operator will typically take 90% of the cost of a premium rate call, with very few overheads of their own.
Users with DSL lines (or similar broadband connections) are usually not affected. A dialer can be downloaded and installed, but dialing in is not possible as there are no regular phone numbers in the DSL network and users will not typically have their dial-up modem, if any, connected to a phone line. However, if an ISDN adapter or additional analog modem is installed, the dialer might still be able to get a connection.
Malicious dialers can be identified by the following characteristics:
Therefore links in spam emails should never be opened, automatically started downloads should be canceled as soon as discovered, and one should check on each dial-up to the internet to see whether the displayed phone number is unchanged. Another way to protect oneself is to disable premium numbers through one's phone services, but of course this disables all such services -- even the honest ones.
Another way of prevention is through the use of anti-spyware programs. Many recent anti-spyware programs can detect and remove dialers, as well as many other forms of malware. Some popular examples include Ad-Aware, Spybot - Search & Destroy, and AVG Anti-Virus.
However, the best way of prevention is by using common sense. Never visit links and sites that are potentially unsafe, and use protection at all times. If an email is sent from an unknown stranger, do not open it (or click on the links contained within) until you can verify that it is sent from a trusted source.
The law contains the following regulations: