Display and Keyboard Assembly

Diagram of DSKY interface, showing LM and CM lights

The Display and Keyboard Assembly (DSKY) was the main interface between the crew and the Apollo Guidance Computer which controlled the Command and Service Module.

Overview

The DSKY is split into three functional areas:

• The LED display, which is used to show information about the program which is running, data relevant to the program, and data that the astronaut is entering into the program.

• The lights panel, which indicates an unusual situation in the computer (e.g. a program error).

• The keyboard, which is used to enter new data to the program and confirm operations that are difficult or impossible to reverse (e.g. verifying an engine burn before ignition).

Programs, Verbs and Nouns

Interacting with the DSKY requires an understanding of the basic design of the AGC software. In particular, the concepts of Program (also referred to as Major Mode), Verb and Noun.

The Program determines the mode the computer is operating in. For example, Program 11 in the CM monitors the launch of the Saturn and displaying data on the DSKY in the LED display. Program 63 in the LM controls the braking phase of the automated lunar landing. So you need to know the program number to determine what the computer is trying to do.

The Verb specifies further optional actions that the computer can take, which may or may not be valid in all programs. For example, Verb 06 is used to display data from the computer on the LED display, while Verb 75 is used to start the launch monitoring program running if the computer didn't start it automatically at liftoff.

The Noun provides further information to the Verb. In the Verb 06 case, this specifies what data the computer should display; for example, Verb 06 and Noun 36 shows the current setting of the AGC's internal clock, whereas Verb 75 doesn't care what the Noun is set to.

For further information which Programs, Verbs and Nouns are supported, see pages specific to the version of the AGC you are using.

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