My Apartment Security System

by Craig Wilcox

My apartment building has a typical security system where someone can press a button corresponding to my apartment number from the front entrance to the building and I can then talk to them through the security system. If I decide to allow the person entry to the building, I can unlock the front door from my apartment to let the person in.

However, the interface for this system from the apartment leaves much lacking. The designers of the system chose a telephone metaphor for the interface. On the wall in my apartment, I have what looks like a corded telephone without dialing buttons. When the receiver is picked up from its cradle, a contact switch is opened which enables me to hear sound from the microphone at the front entrance to the building. This handset, a loud buzzer, and one contact switch are the entirety of the interface. Since the interface itself is so simple, I will critique it in the contexts of each task that it can be used for.

Talking to someone at the building entrance

To talk to someone at the front entrance, they must first buzz your apartment and then you simply pick up the handset and talk. This is actually the strength of the design because the metaphor of answering a telephone works quite well.

Disallowing access to someone at the building entrance

After talking to the person, as described above, simply hang up the receiver. This also follows what is logical for a telephone conversation.

Unlocking the front door to the building

This is definitely the worst aspect of the interface. To unlock the front door, you must first be in a talking mode as described above. Then, you need to close the contact switch on the receiver for about two seconds before releasing. This action then closes a relay that unlocks the front door for about two seconds. The problem is that this process has a fifty percent success rate. This is because success requires both the person in the apartment to have correct timing to unlock the door and the person at the entrance to open the door during the two seconds that the relay is open for the door lock. Unfortunately, there is no feedback to the person in the apartment whether the door unlocked or the person successfully opened the door. This can be very frustrating for both parties.

Spying on people talking around the front door

To listen in on conversations around the front door, simply lift the receiver and listen. I do not know if the connection is two-way or not, since I have never tried talking during this situation. I assume that this is not the intended use of this device. However, it is good to be aware of when you are in front of my apartment building.


Basically, the interface for unlocking the front door is bad enough that I do not even use it anymore. I would rather walk down three flights of stairs than risk the chance of losing a pizza delivery or a visitor thinking that I do not want to let them in. I guess that pretty well summarizes my opinion of the interface.