Better be deaf

As promised, today, I am going to share with you an amusing anecdote which demonstrates how a poorly designed user interface can ruin a good and simple system into something which is hardly usable.

I already talked you about my elevator front panel. I know another device in my apartment building which deserves, I believe, some words: my entry phone!

In fact, my entry phone has nothing special compared to the other entry phones in the building. They are all the same. Its usage is also very usual. Each phone is connected to a microphone located at the entrance of the building. When a visitor wants to enter the building, she presses a button close to the door. The host hears a short tone melody which warns about the presence of a visitor. The host comes to the entry phone, and speaks into the microphone to the visitor. Eventually, the host lets the visitor enter the building by pressing another button. As I said, nothing unusual.

But the entry phone has a second functionality. There is also a ring at the door of the apartment. That ring is connected to entry phone as well. When a visitor rings, the host hears a melody which warns about the presence of the visitor (deja vu?). The host comes at the door, looks into the peephole, and eventually opens the door and welcomes the visitor.

Perhaps you already figured out what is the problem: the tone melodies. In both the scenarios, the entry phone plays a tone melody and there is no easy way to know where the visitor is: at the entrance of the building, or at the entrance of the apartment. One could argue that any visitor will first come at the entrance of the building, but it is no help for several reasons: the entrance of the building was sometimes left unclosed by a previous visitor; or you are sometimes visited by your own neighbor; or some people are actually visiting all the inhabitants so they need obviously to enter the building only once.

At the beginning, I did believe it was only me. Perhaps I have a bad sound memory, or perhaps I would finally learn for what event is each melody. But surprisingly, ten years after, the problem remains the same. Each time the phone entry plays the little music, I don't know where to go: at the entry phone or at the door. My wife does experience the exact same problem. But it seems my neighbors too! A few weeks ago, I needed to talk to one of them. So I rang at his door. After some seconds, I clearly hear my neighbor not too far behind the door trying to vainly speak in the entry phone: "Hello? Hello? Who is it?" So I just knock at the door to tell him he should stop speaking alone in the microphone and come at the door instead.

The fact is that the system exposes two different features through a problematic user interface:
  • It uses a single communication channel: sound. No light, no display, nothing else. But it's not the worst issue, as most of the existing user interfaces do the same without any major problem (phones, traffic signs, and even software applications which most of the time, focus on visual user experience only.)
  • Both the features are exposed through symbols (the melodies) which are totally disconnected from their meaning. They do not evoke anything. They are just a short abstract series of unrelated tones without any semantic. You have to be very imaginative to be able to associate them with one feature or another.
I am unsure what solution could have been chosen to design an effective interface for that system: visual support, multiple sound source (at the door and at the entry phone), better distinct melodies, artificial voice? (I'm a bit reluctant about using artificial human voice when not absolutely necessary. It tends to be quickly irritating. This is something I will probably come back later in a future post.)

What I know for sure is that the designer should have issued a meeting notice for some brainstorm with his colleagues.

No comments: