1) For the 1/8'' miniplug earphones you use for the cellphone, why is it made only with one earpiece? Is it because driving without hearing your surrounding environment is dangerous or is it because it is mono?

2) Is there such thing as a 1/8'' to 1/4'' converter? The company Skullcandy makes headphones that work for cellphones so you can listen to music while you talk, but the wire consists of TWO plugs. One goes in your cell other goes into cd/mp3/md player. I'm wondering if there's such thing with one plug.

1) The average telephone signal is only low quality mono, just pick up your regular telephone to figure that out, so that gives an idea as to the reasoning behind the single earplug idea. When you think about it, it's more practical having one earplug, as we're used to having one ear to the phone and all. And I suppose business type people are used to multi-tasking while on the phone, and having only plug enhances their ability to do so. 1/8 minijacks are of course capable of outputting stereo sound however- I'd say they're used by headsets because of their small size.

2) Definately, just go to any good hi-fi store and sneak around in the adaptor section- adaptors come in just about any variety you can think of, and with a little ingenuity you could most probably combine two or three adapters to get the setup you're talking about.