Ordinateur distant
          Terminal X                    +------------------Logiciel--------------------+
 +-Matériel-+  +------Logiciel-----+    +-Espace utilisateur--+-----Espace noyau-------+
 | +------+ |  |  +---+            |    |            +-----+  |  +----PTS----+   +---+ |
 | |Souris|-|--|->| D |            |    |            |Shell|<=|=>|/dev/pts/42|<=>| D | |
 | +------+ |  |  | R |            |    |            +-----+  |  +-----------+   | D | |
 |+-------+ |  |  | I |   +-----+  |    |  +-----+   +-----+  |     +-----+      | L | |
 ||Clavier|-|--|->| V |   |     |  |    |  |     |<=>|xterm|<=|====>| PTM |<====>|   | |
 |+-------+ |  |  | E |   |Serv.|  |    |  |Serv.|   +-----+  |     +-----+      +---+ |
 | +-----+  |  |  | R |<=>|  X  |<=|=//=|=>|  X  |   +------+ |                        |
 | |Ecran|<-|--|--| S |   |     |  |    |  |     |<=>|Clt. X| |                        |
 | +-----+  |  |  +---+   +-----+  |    |  +-----+   +------+ |                        |
 +----------+  +-------------------+    +---------------------+------------------------+
Depuis un terminal X, Alice se connecte à la machine distante, pour y exécuter un shell.
DDL : Discipline de ligne
PTM : Drivers PTY maître
PTS : Drivers PTY esclave