Install ax25-apps by entering the following commands in the terminal:
sudo apt update sudo apt install ax25-apps
AX.25 ham radio applications
This package provides specific user applications for hamradio that use AX.25 Net/ROM or ROSE network protocols: * axcall: a general purpose AX.25, NET/ROM and ROSE connection program. * axlisten: a network monitor of all AX.25 traffic heard by the system. * ax25ipd: an RFC1226 compliant daemon which provides encapsulation of AX.25 traffic over IP. * ax25mond: retransmits data received from sockets into an AX.25 monitor socket.