Install asterisk by entering the following commands in the terminal:
sudo apt update sudo apt install asterisk
Open Source Private Branch Exchange (PBX)
Asterisk is an Open Source PBX and telephony toolkit. It is, in a sense, middleware between Internet and telephony channels on the bottom, and Internet and telephony applications at the top. . Asterisk can be used with Voice over IP (SIP, H.323, IAX and more) standards, or the Public Switched Telephone Network (PSTN) through supported hardware. . Supported hardware: . * All Wildcard (tm) ISDN PRI cards from Digium (http://www.digium.com) * HFC-S/HFC-4S-based ISDN BRI cards (Junghanns.NET, beroNet, Digium etc.) * All TDM (FXO/FXS) cards from Digium * Various clones of Digium cards such as those by OpenVox * Xorcom Astribank USB telephony adapter (http://www.xorcom.com) * Voicetronix OpenPCI, OpenLine and OpenSwitch cards * CAPI-compatible ISDN cards (using the add-on package chan-capi) * Full Duplex Sound Card (ALSA or OSS) supported by Linux * Tormenta T1/E1 card (http://www.zapatatelephony.org) * QuickNet Internet PhoneJack and LineJack (http://www.quicknet.net) . This is the main package that includes the Asterisk daemon and most channel drivers and applications.