Embodiments of this invention provide for coupling an accessory device to a back face of a handheld computer while electrically connecting to the handheld computer through a communications or output port. In one embodiment, the accessory device “piggy-backs” on the handheld computer so that the accessory device and handheld computer form a portable combination. An insertion coupling may be used to detachably secure the accessory device with the handheld computer. The insertion coupling used with embodiments of the invention is preferably a snap-in coupling having one or more biased members. The biased members may be contracted to engage an aperture on a back face of the handled computer. When released, the biased members secure the accessory device to the handheld computer.