1. Memory for many sets passwords, which satisfies the need of the apartment buildings.
2. Could stop the usage in free or memorize any transmitter (control type).
3. Could display the memory position of transmiter (collocate with displayer).
4. Could choose to be the remote control of the electric lock or the rolling door.
5. Could also add infrared ray or smoke detecting server wiring together.
Applicative range：Electric rolling doors of apartments building, elevators for apartments and the entrances factilities of factories.