isdnutils-xtools binary package in Ubuntu Bionic arm64

 This package provides xmonisdn and xisdnload, which are graphical tools
 for ISDN. Each in its own way gives a visual indication of the status of
 the ISDN lines, so that (for example) it is obvious when there is a
 connection.
 .
 They have been split out into a separate package to allow the others
 in the suite to avoid dependencies on the X Window System.

Source package