• • Deafness. • • Visual impairment - moderate. • • Visual impairment - severe. • • • Blindness. • • • Deaf-blindness. • • Cognitive impairment.

The operating pressure required to activate a key may be critical for some people.

Unsuitable pressure may result in mis-keying, either thr size="2" width="50%" size="2" width="50%"ough no contact or repeated operation, and it may even lead to muscle spasm where the user cannot readily release the key.

A means of adjusting the return spring pressure or, alternatively, a range of keypads with differing operating forces, is required to meet the needs of these users.