AsteriskNOW is an open-source Software Appliance from Digium: a customized Linux distribution, which includes Asterisk (the leading open-source telephony engine and tool kit), the AsteriskGUI, and all the other software needed for an Asterisk telephony system. AsteriskNOW is easy to install. It allows you to deploy Asterisk quickly and easily, and offers flexibility, functionality and features that are available only in expensive proprietary business systems.