摘要 |
<p>By providing seven keys in a keyboard so that a pair of keys (3, 4 and 1, 6) is placed at each side of the centre key (7), and one key (2) is placed above and one key (5) below the centre key (7), it is possible, by actuating either one key (Fig. 3), two keys (Fig. 4) or more, to produce up to 127 different symbols. The symbol is produced by pressing that or those keys (1-7) that do not form part of the symbol; this makes the keying operation considerably easier since the entered symbol is seen from the remaining non-actuated keys. This keyboard is thus very compact and will not require such large finger movements as does a usual keyboard with up to 50 keys. If a luminous line (8) is inserted in the keys (1-7), the keyed symbol will appear as a luminous symbol on the non-actuated keys which makes it easier to control and supervise the operation.</p> |