An interface device for communicating between a host device and a conditional access module for performing secure operations, said interface device having a format compatible with a PCMCIA standard and comprising: a housing; a printed circuit board to house components of the conditional access module; a frame substantially describing a contour of the printed circuit board; and a connector panel to connect the printed circuit board to the host device; the housing: extending between a first end and a second end; having two opposite sides; dimensioned to comply with a PCMCIA standard, and comprising: a top cover; and a bottom cover; said top cover and said bottom cover being adapted to interlock with each other; wherein the top cover comprises: a first two top cover tabs located on opposite sides of the top cover towards the first end; and a second two top cover tabs located on opposite sides of the top cover towards the second end; said top cover tabs having: a first section substantially perpendicular to a plane of the top cover; and a second section substantially perpendicular to the first section and lying beneath the top cover; and wherein the bottom cover comprises: a first two bottom cover tabs; and a second two bottom cover tabs; each of the bottom cover tabs corresponding to one of the top cover tabs and adapted such that said interlocking takes place with its corresponding top cover tab; said bottom cover tabs having: a first section, substantially perpendicular to the bottom cover and having a slit (SLIT) adapted to be interlocked with the second section of the corresponding top cover tab; the bottom cover tabs of the housing having a second section forming a hook, an extremity of the hook facing the bottom cover; wherein the frame comprises: a first two grooves corresponding to the first two bottom cover tabs and a second two grooves corresponding to the second two bottom cover tabs, said grooves adapted so that the hooks of the bottom cover tabs can fit inside; a lip below at least part of each groove, said lip adapted such that at least part of the second section of the corresponding top cover tab may slide underneath; and a recess (RCST) adjacent to each of the grooves, said recess (RCST) adapted to allow the second section of the corresponding top cover tab to pass through; said interface characterised in that it is adapted such that: the printed circuit board fits between the frame and the bottom cover while the frame is positioned such that the extremities of the hooks of the bottom cover tabs face the grooves; and when the second sections of the top cover tabs are positioned beneath their corresponding lips, said frame is held within the housing by a combined action of the extremities of the hooks pulling in a first direction on the grooves and the second section of top cover tabs pulling in a second direction, substantially opposite to the first direction, on the lips under the grooves. a top cover; and a bottom cover; a first two top cover tabs located on opposite sides of the top cover towards the first end; and a second two top cover tabs located on opposite sides of the top cover towards the second end; said top cover tabs having: a first section substantially perpendicular to a plane of the top cover; and a second section substantially perpendicular to the first section and lying beneath the top cover; and a first section substantially perpendicular to a plane of the top cover; and a second section substantially perpendicular to the first section and lying beneath the top cover; and wherein the bottom cover comprises: a first two bottom cover tabs; and a second two bottom cover tabs; a first two bottom cover tabs; and a second two bottom cover tabs; each of the bottom cover tabs corresponding to one of the top cover tabs and adapted such that said interlocking takes place with its corresponding top cover tab; said bottom cover tabs having: a first section, substantially perpendicular to the bottom cover and having a slit (SLIT) adapted to be interlocked with the second section of the corresponding top cover tab; a first section, substantially perpendicular to the bottom cover and having a slit (SLIT) adapted to be interlocked with the second section of the corresponding top cover tab; a first two grooves corresponding to the first two bottom cover tabs and a second two grooves corresponding to the second two bottom cover tabs, said grooves adapted so that the hooks of the bottom cover tabs can fit inside; a lip below at least part of each groove, said lip adapted such that at least part of the second section of the corresponding top cover tab may slide underneath; and a recess (RCST) adjacent to each of the grooves, said recess (RCST) adapted to allow the second section of the corresponding top cover tab to pass through; the printed circuit board fits between the frame and the bottom cover while the frame is positioned such that the extremities of the hooks of the bottom cover tabs face the grooves; and when the second sections of the top cover tabs are positioned beneath their corresponding lips, said frame is held within the housing by a combined action of the extremities of the hooks pulling in a first direction on the grooves and the second section of top cover tabs pulling in a second direction, substantially opposite to the first direction, on the lips under the grooves.