The Airlines Electronic Engineering Committee (AEEC), an international body of airline representatives leading the development of avionics architectures, formed the ARINC 661 Working Group to define the interfaces to the Cockpit Display System (CDS) used in all types of aircraft installations. The standard is called ARINC 661 - Cockpit Display System Interfaces to User Systems.

The primary objective is to minimize the cost to the airlines, directly or indirectly by accomplishing the following (from the ARINC 661 - Cockpit Display System Interfaces to User Systems):

• Minimizing the cost of changing or adding new avionic systems to the extent it is driven by the cost of CDS development
• Minimizing the cost of adding new display functions to the cockpit during the life of an aircraft.
• Minimizing the cost of managing hardware obsolescence in an area of rapidly evolving technology.
• Introducing interactivity to the cockpit, thus providing a basis for airframe manufacturers to standardize the Human Machine Interface (HMI) in the cockpit.

ARINC 661 defines two external interfaces between the CDS and the aircraft systems. The first interface is the interface between the avionics equipment (user systems) and the display system graphics generators. The second is a means by which symbology and its related behavior is defined. A user application is defined as a system that transmits data to the CDS, which, in turn can be displayed as visual graphical information to the flight deck crew. A user application can also include software or hardware that receives input from interactive graphics managed by the CDS. The CDS provides graphical and interactive services to user applications within the flight deck environment. When combined with data from user applications, it should display graphical images to the flight deck crew.

ARINC 661 defines an interface between the CDS and user applications (UA) and assumes that the application that controls the interface is within the CDS. On the other hand, ARINC 661 does not specify the "look and feel" of any graphical information.

Features and Benefits
• Incredible flexibility and extensibility for developing user-defined objects/widgets and ARINC 661 cockpit displays
• Easy-to-use graphical editor to speed up ARINC 661 display design
• Powerful Object Model based architecture
• Display layout files are saved in an extensible, human readable XML format facilitating development tracking and revision control
• Interfaces with industry leading requirements tracking tool Telelogic DOORS®
• The solution can be used by teams of HMI developers to jointly develop the look and feel of the Cockpit Display System (CDS) with the User Applications (UA) or avionic subsystems. It enables seamless collaboration between OEMs, CDS suppliers, and UA developers.