isdnlog 1:3.25+dfsg1-9ubuntu1 (s390x binary) in ubuntu bionic

 This package provides a set of utilities that can log ISDN connections and
 calculate the cost of calls. If sufficient data is available, it can even
 recommend which alternate carrier would have been cheaper for a given call.
 For countries where calls are charged per discrete unit, it can disconnect
 the line just before the next unit starts.