Secured keypad devices

1. A data entry device comprising:

a housing including a top housing portion including key apertures;

a key assembly including a plurality of depressible keys, which partially extend through said key apertures, and a corresponding plurality of key contacts which do not underlie said key apertures; and

a protective partial enclosure at least partially surrounding said key assembly, said protective partial enclosure including at least one anti-tampering grid formed of a multiplicity of interconnected anti-tampering electrical conductors and being formed with grid apertures aligned with said key apertures for permitting displacement of said depressible keys therethrough;

said key contacts underlying said at least one anti-tampering grid; and said key assembly being constructed such that said key contacts define an open electrical circuit when a first key of said depressible keys is depressed and define a closed electrical circuit when a second key of said depressible keys is not depressed; and

wherein said key assembly further includes a printed circuit board and a plurality of depressible key elements which are displaceable relative thereto, said printed circuit board defining a first key contact for each of said plurality of depressible key elements, which does not underlie a corresponding key aperture, and said each of said plurality of depressible key elements defining a second key contact, which does not underlie a corresponding key aperture, for selectable engagement with said first key contact.

2. The data entry device according to claim 1 and wherein said anti-tampering electrical conductors are electrically connected to anti-tampering detection circuitry.

3. The data entry device according to claim 1 and wherein said protective partial enclosure further includes a bottom anti-tampering grid underlying said key assembly.

4. The data entry device according to claim 1 and wherein said plurality of key contacts do not underlie said grid apertures.