Ambiguous “On” Indicators on Television Sets and Monitors

I’m currently taking a course on Human-Computer Interaction (HCI). The instructor advised us to keep logs of things we notice in the world that relate to the course material. This is one of my log entries.

One item I noticed today was the On indicator on a Samsung television at work. It’s a large flat-panel screen that we have connected to a PC for presentation purposes in a small conference room. I was preparing for a presentation and sat down at the keyboard and mouse. The power light glowed amber, so I wiggled the mouse. Nothing. I pressed CTRL-ALT-DEL. Nothing. I checked to make sure that the PC was on, and then I checked to make sure the cables were connected. Everything looked correct–why wasn’t the screen getting a signal?

Bottom panel of a television set displaying an amber light. Note that although the indicator light is near the power symbol, it could be much closer.

As it turns out, the screen was not powered on! Once I pressed the power button, the indicator light changed from amber to green and the Windows login was displayed on-screen. Most of the monitors I am used to use an amber light to indicate that the screen is in a power-save mode, usually because it is not receiving a signal from the input device. When they are powered off, there is no indicator light at all–which makes sense if there is no power to the device! Since most modern electronics still draw some power when they are plugged in (“vampire” devices because they leech electricity even when not in use), this could potentially indicate that the device is, at the very least, plugged in.

My television set at home, a Samsung LCD set, also has an ambiguous On indicator: it displays a solid red light to indicate that it is Off and a blinking red light to indicate that it is On. Personally, I consider this to be ridiculous: which is Off and which is On? Red On and Red Blinking don’t particularly have a natural mapping, in my mind, to On and Off. (Red and green would be a superior combination, but would require 2 different LEDs.)

I do have the television, along with most of the other components of the entertainment system, connected to a Belkin Conserve power strip and surge protector, so that I can shut off all the vampire devices while I am asleep or at work. Because of this set-up, the lit-up Off indicator becomes helpful: it’s an easy way for me to know whether the power strip is on or not. Of course, if the power strip is on, I still don’t know whether the TV set is on or not.

In both cases, the televisions are trying to provide the user with information about their statuses. However, in the first case the message is easy to misinterpret–in part because users may have familiarity with devices where the same signal is used to convey a different message. In the latter case the message is entirely ambiguous because the two opposite states are represented by similar signals.

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