Here's what I want, after getting tired of having to yell into my cell phone:
http://www.pokia.com 
Info is very hard to come by, but it looks like I might just be able to get
by with a simple adapter between the standard 2.5mm cell phone headset plug
and an RJ handset plug.  The typical telephone handset of the 90's seems to
use the same mic and speaker components.

5 responses total.

Heh, that's pretty cool.  I've often remarked that the old-fashioned
rotary-dial phones had handsets that are much more comfortable to hold
than modern phones.

What would be really cool would be to fabricate a cell phone charger
stand out of an old phone, with the old handset and hookswitch tied into
the cell phone.  It should be possible, since most cell phone headsets
have a button that can be used to answer calls.

I suspect you'll have to replace the carbon mic in the handset with a
modern condensor type, but that shouldn't be too hard.

I still need to find out how the button on a cell phone headset is used. 
Another reason I need to buy a cheapie to vivisect.

The carbon mics aren't that common - yeah, if I dug up an old 70's classic
I'd have to deal with that, but there are a lot of nice handsets from the
deregulation era with modern parts.

The instruction manual for my 2m HT has a pinout for the headset plug. 
For some reason the company that made my cell phone wasn't as thoughtful. ;>

You're going to need a cheapie anyway, for the connector.  Most cell
phones I've seen use a four-conductor, 3/32" plug for the headset. 
3/32" plugs aren't commonly available with more than three conductors.

The cell phone connectors are wildly different, sometimes even from the same
manufacturer.

So anyway, I found a three-pack of cheapo earbuds for my Ericsson for about
$15, perfect for hacking up.  

Turns out that the components are pretty much the same, a little dynamic
speaker and a tiny little electret capsule mic.  The button just shorts out
the mic, which has a couple volts DC bias.  With just a basic adapter cable
between handset and phone it worked.  But there's a lot of noise from the
digital radio, so I've got to do it with shielded cable next.

Swapping in the mic capsule from the official cellphone headset did the trick.
Much less noise, even with unshielded wire to the phone.

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