KM 30-12 : for info about the bus : http://www.techunited.nl/wiki/index.php?title=User-friendly_Bus_for_Simulink ALWAYS use the "bus_manager" to create, edit or add busses. Two blocktypes exist, an assign bus, and a decode bus, these blocks can be found in Turtle2/Libs/Simulink/Bus/bustest.mdl. They are (and can) not be included in the standard Simulink library. Turtle2/Communication/sf_multicast/mccomm_receiveReboxCommands.c is an example for having a bus as output of an S-function. An example of an bus as input can be found in Turtle2/Communication/sf_multicast/mccomm_motion.c (GN 01-01). The TRCbus and motionbus are (kind of) implemented in motion_turtle.mdl. Please report bugs and comments to me! KM 30-12 - refbox_comm.c is obsolete - mccomm_joystick is obsolete