The mailing system your are referring to is called UUCP (Unix to Unix copy protocol). It can use serial link or IP as a transport to transmit batches of tar-gzi

The mailing system your are referring to is called UUCP (Unix to Unix copy protocol). It can use serial link or IP as a transport to transmit batches of tar-gzipped emails. Binaries were usually uuencoded in mail body (if you are on FreeBSD, type: man uuencode).