+-------+                       +-------+
$TTKS:  |       |-------------> RCSR:   |       |
        +-------+                       +-------+
 
        +-------+                       +-------+
$TTKB:  |       |-------------> RDAT:   |       |
        +-------+                       +-------+
 
        +-------+
$XTTNR: |       |-------------> TNRRTN: RETURN 
        +-------+