If the user has a powered wheelchair, the aid and its mounting should not impede the user's ability to see where they are going. Accessing By accessing we mean how a person uses the piece of equipment. This can be direct selection , where an individual has direct physical contact with the communication device to make a choice ie touching the front of a communication aid to produce a spoken message. Direct access can be achieved by any part of the body such as the toe, finger or elbow. Access may also be by indirect selection , where an interface of some kind is used between the user and the device ie a switch is pressed at an appropriate time to produce a spoken message.
Some communication devices offer text, some offer symbols and some offer a mixture of both.
The nature of the selection set offered by a device must match the abilities of the user. In a simple example, a user who was unable to spell would not consider using a communication device that offered text as the only selection set. The way that information is displayed to the communication aid user can be crucial to the success of a communication device. Static screen devices are those devices that make use of paper-based overlays. The symbols or icons presented on the overlay can be used for identifying where single messages are stored but can also be used in series of combinations to enable the user to produce unique and complex phrases.