1. A keyboard switch means for making a plurality of contact closures, comprising a conductive diaphragm, a plurality of pie sections, with at least two of said sections terminating on different radii, key and distributor means for moving said conductive diaphragm into contact with said pie sections, whereby as said key is depressed, at least two of said sections contact said diaphragm at different times.

2. A serial keyboard apparatus comprising elastic diaphragm switch means for making a plurality of contact closures comprising a conductive diaphragm, a plurality of pie sections, each said section terminating at different radii, with each pair of pie sections terminating on adjacent radii defining a bit in the code, actuating means for bringing said diaphragm into contact with said pie sections in a serial fashion, a positive voltage source a negative voltage source, each said pair having one pie section connected to said positive source and the other pie section to said negative source, voltage summation means connected to said diaphragm for summing the voltages of all said pie sections in contact with said diaphragm, whereby as the key is depressed, the diaphragm contacts the pie sections in a serial manner and a summation of the voltages of said sections represents the serial code output of said switch.

3. An elastic diaphragm switch array, comprising a conductive diaphragm, a plurality of pie sections, actuating means for moving said diaphragm into contact with said pie sections, each said pie section terminating at a different radius from the axis of said actuating means.

4. In an elastic diaphragm switch, a plurality of contact closures comprising a conductive diaphragm, a plurality of pie sections, actuating means for bringing said diaphragm and pie sections into electrical contact, at least one of said pie section terminating at a radius different from the radii of termination of the other sections from the axis of said actuating means.

5. An elastic diaphragm switch keyboard for generating at least two output codes, comprising a plurality of switch arrays, each said array comprising at least two groups of pie elements with one group terminating at different radii than the other group, and with said one group connected to output pins associated with one code and said other group connected to output code pins associated with the second code, a conductive diaphragm, and actuating means for bringing said diaphragm and said pie elements into electrical contact.

7. In an elastic diaphragm switch keyboard, a switch array comprising a plurality of pie sections, with one pie section extending into the center, and a second pie section terminating at a radius which is greater than the radii at which the remaining pie sections terminate, conductive diaphragm means, and actuating means for bringing said pie sections and said diaphragm into electrical contact whereby mechanical strobe and rollover protection is provided.

8. In an elastic diaphragm switch keyboard having a plurality of switch arrays, each array having a plurality of pie sections, rollover protection means comprising for each said array a control pie section extending to the center axis of the corresponding switch actuator, and means for detecting simultaneous actuation of two said control sections in different switch arrays.

9. In an electrical diaphragm switch array, mechanical strobe means comprising a conductive diaphragm, a plurality of pie sections, actuating means for bringing said diaphragm and pie sections into electrical contact, one of said pie sections terminating at a radius larger than the radii about the axis of said actuating means at which the other pie sections terminate.

10. In a battery-operated elastic diaphragm switch keyboard, a switch comprising a conductive diaphragm, a plurality of pie sections, actuating means for bringing said diaphragm and said sections into electrical contact, one of said sections terminating at a different radius from the others and said one section being connected to a battery for drawing current to operate the keyboard only when the switch array is actuated.