Dialer

A dialer is a piece of software which is designed to dial the telephone automatically.

Automated dialers store names and telephone numbers and enable to you easily contact people without remembering phone numbers.

Most automated dialers will retrieve contact information from other databases, such as your Microsoft Outlook Contacts list.

Some automated dialers will also dial a telephone number at regular intervals until a person answers the phone. When the person answers the telephone, the automated dialer will sound an alarm to let you know that the called party is on the line.

Malicious uses
A spyware dialer is a malicious program that installs itself onto a computer and attempts to dial telephone lines at other locations, often incurring expensive phone bills for the victim. A dialer is much different than the spyware typically bundled with free software downloads. They are however, difficult to detect and furthermore prove that the dialer is responsible the chargers. It is also difficult to distinguish a legitimate dialer from a spyware dialer, a factor that has made this infection much harder to control.