BerkeleyUnix networking devICe whICh appears to an applICation program as an ordinary terminal but whICh is in fact connected via the network to a process running on a different host or a windowing system. Pseudo-ttys have a slave half and a control half. The slave tty (/dev/ttyp*) is the devICe that user programs use and the control tty (/dev/ptyp*) is used by daemons to talk to the net. (1994-11-08)