A telephone set having an optical readout of the telephone number which is entered onto the telephone set. An optical display is electrically coupled by means of a control circuit to the standard telephone dialing circuit such that the number dialed onto the telephone set is displayed on the optical display. The optical display can be included directly in the telephone set housing or can be provided as an attachment to the telephone set housing. A memory storage is provided which can temporarily store the number until the user has checked that the entire number is correct and then the number will be transmitted onto the telephone line.