NUL was also a common delay character, and one can find some of the delay mechanisms, enshrined in the POSIX standard as part of the General Terminal Interface,

NUL was also a common delay character, and one can find some of the delay mechanisms, enshrined in the POSIX standard as part of the General Terminal Interface, in Linux even today. (They are largely gone from OpenBSD and FreeBSD.) * http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap11.html#tag_11_02_03 http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_...