ASTi systems generate three types of PDUs related to DIS simulated radio communications: Transmitter PDUs, Receiver PDUs and Signal PDUs.

Transmitter PDU: contains data describing the state of a transmitter. See: http://www.sisostds.org/dis-dd/pdu/dc.htm

Receiver PDU: contains data describing the state of a receiver. See: http://www.sisostds.org/dis-dd/pdu/fd.htm

Signal PDU: contains voice, audio or tactical message data. See: http://www.sisostds.org/dis-dd/pdu/f4.htm

In addition ASTi systems are capable of receiving and processing Entity State PDUs. It works like this: if the Site, Host and Entity IDs assigned to an ASTi radio match those of an Entity State PDU present on the same network, the ASTi radio software will extract the geocentric world position values from the Entity PDU and attach them to the world position setting of the associated ASTi radio. After a successful entity attachment, the ASTi radio server applies propagation effects to the radio as if it were collocated with the entity. Detailed information about Entity State PDUs is available at this site: http://www.sisostds.org/dis-dd/pdu/29.htm