a secured housing for an electronic device having an electronic memory mounted therewithin is provided which has an access aperture which provides tamper proof security and electro - magnetic interference protection while permitting access to the memory for reading the information maintained in the memory . opening of the access aperture disables the electronic device from further operation by unlatching a switch which disconnects the electronic device from its power supply while preventing relatching of the switch to reactivate the electronic device . use of the access aperture provides a visible indication of access to the interior of the housing . in one embodiment of the invention , the electronic device is an electronic postage meter and the electronic memory is a nonvolatile memory containing postage accounting information .