A portable electronic device, for example a cellular telephone or a personal digital assistant, has an internal screen for the display of information, the electronic device also having an external screen arranged to receive information from the electronic device and being capable of displaying this information on an electro-optic medium. There is also provided a cellular telephone having a visual indicator comprising an electro-optic medium having at least two different display states, the electro-optic medium being arranged to change its display state when a call is received by the telephone.