If you have a Panasonic 8x24 phone system installed to manage your business phone and voicemail capabilities, you can expand this system to talk to visitors and allow them entry without getting up to open a door. The Door Phone/Door Open Card and supports up to four Door Intercom Stations to communicate with guests arriving at any entry to your building. Once you've established who's there, you can let them in with the press of a button by installing a Door Strike Mechanism. The phone system, intercoms and door strike mechanisms are sold separately.