Abstract: A radio modem for fitting to equipment such as a portable computer, in particular, the modem being deigned to be inserted in a slot provided in the equipment, and the modem including two elements which are disposed relative to each other and which are fitted so as to form a memory card reader, and wherein, for the slot having dimensions adapted for receiving a modem in the form of an “equipment” card of determined thickness, each of the two elements is implemented by means of an equipment card of thickness that is smaller than the determined thickness.