2.3 When deploying more than one version of a device, ensure that the user interfaces are similar

Telecommunications services may be delivered through a number of different devices, which should use a similar presentation and interaction style. The layout of controls and keypads and the location and orientation of slots or dispensers for cards and coins should be the same on each version of the device. Having completed a task on one type of telephone, the user should be able to complete the same task on a different type by carrying out a similar sequence of steps.


People with cognitive or learning disabilities find it difficult when the presentation, interaction style or task flow varies. If there is no consistency between different telecommunications devices, users will have to repeatedly relearn the procedure.

Consistency is also vitally important for users who have difficulty perceiving the instructions and controls. Memorising a routine sequence of button presses to make and receive calls is the main strategy employed by blind telephone users. If the position of buttons is different from one device to another, their standard sequence is of no use to them.

Directions and Techniques

Adhere to standards

Achieve consistency with other telecommunications devices by using international or industry standards wherever possible. Standards exist for such things as symbols (e.g. ISO 7000 & 7001), colours and keypad layouts.

How you could check for this:

There are no specific test methods recommended for this guideline.