This page has been created to collect all the different terminology for switch and scanning functions.

There is often confusion because various AT professionals with different interests use alternate terms for the same (or similar) functions. In some cases there is ambiguity (e.g. directed scanning and direct access).

This list has been compiled as a starting point. I’m sure that further improvements can be made using key sources such as:

• Cook A.M. & Hussey S.M., 1995, Assistive technologies: principles and practice, Mosby, ISBN 0 8016 1038 9
• Nisbet P. & Poon P., 1998, **Special Access Technology**, CALL Centre
• Colven D. & Detheridge T., 1990, Common Terminology for Switch Controlled Software, ACE Centre, Oxford. ISBN 1 85379 112 1
• Gary Derwent's **Scanning Factor's Diagram** (PDF)

In addition, we have recently published Switch Access to Technology - a comprehensive guide with a similar aim - so maybe we should make the list below reflect that. ( — Simon Judge 2006/11/21 )

For each item, a brief description is provided followed by the list of alternate terms. It is intended that the most common, useful or appropriate term will be used as the heading.

The collection of objects or items from which a selection is made. Alternatives:

• Selection Set
• Grid
• Overlay
• Page

Any item in a selection set may contain more than single letters or commands. They can contain complete words, phrases, sentences or even longer texts. The Items may only display a symbol or picture but the item is capable of sending the complete text to another application or output it as speech.

This is the process that is used to move the highlight from item to item. Alternatives:

• Scanning Movement
• Switch mode

The selection advances automatically. Alternatives:

• AutoScan
• Automatic scan

The selection advances each time the user presses and releases the switch. Alternatives:

• StepScan
• Directed scan
• Tap to advance

The selection advances whilst the user is holding the switch. Alternatives:

• UserScan
• Hold to advance
• Inverted scan

The order in which the cells are highlighted. This can include groups of items such as rows or blocks. Alternatives:

• Scanning Method
• Scan mode

Cells are highlighted individually, starting in the top-left corner and progressing to the right along each row in turn. Alternatives:

• Single
• Simple scan

Cells are grouped so that multiple cells are highlighted together. When the group is selected, cell(s) withing that group are highlighted to narrow down the seleciton.

Each row is highlighted in turn. Once a row has been selected, the individual cells in that row are highlighted.

Each column is highlighted in turn. Once a column has been selected, the individual cells in that column are highlighted.

A group of cells are highlighted. The selection set (grid) is either quartered or divided into logical groups according to cell function. Alternative terms:

• Block scan
• Nested scan
• Quaternary scan
• Custom block scan

There are many factors that can be adjusted other than the rate at which the scan advances.

Alternatives:

• Scan speed
• Forward scan time
• Scan delay

Alternatives

• First scan delay
• First scan time
• Initial scan time
• Scan delay on first item

Some scanning methods allow the user to select the highlighted item by leaving the highlight unchanged for a period of time. If the switch is not pressed for this time, the highlighted item is selected.

The input can be filtered to ignore accidental or unintentional switch presses.

Minimum time for switch press; shorter presses will be ignored. Alternatives:

• Input acceptance
• Minimum switch press time
• Ignore presses shorter than

Minimum time between switch presses. If the switch is pressed too soon after the previous press it will be ignored. Alternatives:

• Post acceptance delay
• Repeat time
• Ignore repeat sooner than