All the capabilities set forth in these specifications are currently available from industry in various degrees of functional adequacy except for access to screen memory for translating bit-mapped graphic images. Access problems concerning the input interface to a microcomputer differ by the type and severity of the functional limitation of the employee. Some users with disabilities are capable of using a keyboard if it can be modified slightly. Other users with disabilities require an alternate input strategy. Sequential activation control provides an alternative method of operation by enabling the user to depress keys or buttons sequentially.
Some programs require a mouse or some other fine motor control device for input.
However, some users with motor disabilities cannot operate these devices. The capability to connect an alternative input device can be made available to a user who is unable to use a modified standard keyboard. This feature supplements the keyboard and any other standard input system used. A typical microcomputer generates repetitions of a character if that key remains depressed. This is a problem for users without sufficient motor control.