Dialer

[PussyCat]

A device or piece of software for calling telephone numbers automatically.

[Oralee]

A computer program that causes your [modem] to [dial] a number to a computer server. This is meant to allow the caller to access/download files from the server.
Almost all dialers are for pornography. They may claim to be free, but always go to long-distance telephone numbers. These numbers are usually equivalent to 1-900 numbers in the U.S. ([the numbers] vary from county to country). The caller can end up paying a ridiculous amount of money in phone bills.