ToneDef is a small, powerful open-source tone dialer featuring full DTMFblue box, and red box modes.

Dial using the keypad buttons, enter a predefined sequence for automatic playback, or select an entry from your contact list. Newer releases include an ever-growing bank of international tones.

A small slice of phreaking history!

UPDATE: An HTML5-based version of this tool is currently being worked on.