Technical data

ASTi DACS: Operation & Maintenance Manual (Version 4, Rev. B.1) www.asti-usa.com

Network Interface

Host Simulation Interface

In order to manipulate or drive the sound and communications models developed on the DACS, a

host simulation computer will normally provide simulation state and sound model control param-

eters such as engine RPM, radio frequency, radio position, communications panel switch settings,

etc.

This data is transmitted over an ethernet network to the DACS and received via the Host Interface

network card. For systems with two network cards, the Host Interface card will be marked to

avoid confusion.

Communications with the DACS are asynchronous. The host computer transmits packets at the

host deﬁned iteration rate. The DACS Ethernet hardware receives and buffers the packet in local

memory. With each DACS model iteration, the Model Builder application software uses the latest

receive packet for host input data.

Some model state data and system health parameters can also be transmitted back to the host.

Packet transmission for data being returned to the Host can take place each model iteration or be

reduced in frequency via system start up parameters.

Data received is buffered and “brought in” to the model using various Control objects available in

the Model Builder development environment.

The user can inspect and modify packet data as well as network modes and parameters through

both on screen displays and also through the start up conﬁguration ﬁle.

For transferring simulation state parameters, the DACS supports IEEE 802.3 standard UDP level

protocol with IP addressing.

The use of UDP facilitates the reception of state data from multiple simulation sources by selec-

tion of independent port numbers.

The user will need to conﬁgure the DACS with the appropriate network settings to ensure proper

network operation. See the Model Builder Reference Guide section called “Ethernet Conﬁgura-

tion Commands” for complete Conﬁguration File command line information.

DIS Interface

DIS (Distributed Interactive Simulation) is a simulation protocol standard developed jointly by

industry and the military to enable interoperation of simulation and training devices over local and

wide area networks.

One of the more difﬁcult and often underestimated aspects of simulation over local and wide area

networks is achieving a realistic radio communication environment.

With the DACS DIS option active the local radio and intercom modeling performed by the DACS

is extended over the local and wide area network. Communication simulation between multiple

DIS compatible network devices is invisible to the user with full radio modeling across systems.

All released versions of the DIS standard are supported and can be user selected.