cu 1.07-23 (s390x binary) in ubuntu xenial

 The cu command is used to call up another system and act as a dial-in
 terminal (mostly on a serial line). It can also do simple file transfers
 with no error checking.
 .
 cu is part of the UUCP source but has been split into its
 own package because it can be useful even if you do not do
 uucp.