QjackCtl is a simple Qt application to control the JACK sound server daemon, specific for the Linux Audio Desktop infrastructure. Written in C++ around the Qt4 toolkit for X11, most exclusively using Qt Designer. Provides a simple GUI dialog for setting several JACK daemon parameters, which are properly saved between sessions, and a way control of the status of the audio server daemon. With time, this primordial interface has become richer by including a enhanced patchbay and connection control features.