Cell phone chip idea
 

I often see people with more than 1 cell phone, which led me to think why not have a cell phone chip which can accept incoming calls from two numbers, to know which number the person is calling you from you can have a message on the screen which says something like "incoming call to xxxxxx" and when dialling you can choose which number to dial from.

Is there something like this already implemented, if so would it be possible for cell phone companies to implement it?

My cell phone already accepts calls from MORE than two numbers, and shows me the calling number.

As for having two numbers for one phone, that's been possible on land lines since the early nineties. I used to have my business number and my home number on the same line. You get a different ring for each number. It didn't sell well for land lines, so the market probably doesn't care about it.

The distinctive ring could also mess up other features that are communicating between rings on a standard phone. That shouldn't be a problem with cellular, though, since the communication paradigm is entirely different.

Heh, I think he meant to say it the other way around. ;)
I think you're right. I remember having this years ago. I always thought of it as a cheap replacement for a second land line, and so it had a bit of merit. For cellular phones, while it would certainly be possible to implement something like this, I don't see the point. Cell phones by their very nature are personal devices, and so there's nothing to be gained. Also, the fact that many (most?) have caller ID and the ability to program distinctive ring tones based on callers means that even if you plan to share the phone, you can achieve the 'I know who the incoming call is for' without needing a special service.

The benefit he is trying to achieve? That some people carry a personal phone + a business phone. If they could have both numbers on the same device, it would reduce confusion, cost, and the number of batteries to charge.

It seems like I came across something like this on the net the other day. I didn't pay it any attention since I refuse to carry a cell phone or a pager or anything that ties me to the real world.

Yeah, Dual Sim Phones, or Dual Phone numbers on the 1 sim, they exist.
The downside to the Dual numbers on 1 sim is that you have to activate 1 or the other, the dual sim phones let you have both going at once.. hopefully there is some error checking in there to prevent the second number from ringing whilst the first is on a call.

Dual sim phone:
http://www.fonefunshop.co.uk/dualsim/#grey

Dual Phone number sim card:
http://www.optus.com.au/portal/site/...0029867c0aRCRD

On land lines, a ring to the second number, if the first was busy, was like a call-waiting.

Strangely enough, I think any cell phone made since the late 90's does this.

:p