An FED and a method of manufacture are provided. A selected memory cell is coupled to the local data line pair to develop a differential local data line voltage. The SMS message can include a notification that subsequent communications directed to the wireless number associated with the wireless unit are to be routed to the destination number associated with the wireless unit. The objective changing device makes it possible to adapt the laser-based ophthalmological device for new applications without the need for extensive reconfigurations andor costly vario-lense objectives. The method further includes receiving, through the user interface, one or more management instructions for managing the one or more keys, updating the first set based on the one or more management instructions, and storing the updated set and the user identifier associated with the updated set in association with the sponsor.