Check out the author’s website, http://www.neatinformation.com/, for lots of interesting articles. If you link to this instructable from another website, please include a link to the Neat Information website.
Note - You will need basic electronic skills to build the project in this tutorial. You will also need to do some research to verify whether or not it will work with your phone and what connectors you will need. Use this information at your own risk; do not complain if it doesn't work for you. Only use as prescribed. Your mileage will certainly vary.
Here’s an interesting retrohack which is actually more practical than it seems at first glance – connecting an old telephone handset to your cell phone.
It’s been done before, primarily with Bluetooth. Many of the mods just repackage a Bluetooth headset by removing the handset’s original microphone and speaker and putting the Bluetooth mike and speaker into their locations with whatever extra wiring is required. A few use the original handset’s mike and speaker and connect the wires to a Bluetooth module. But this version is non-invasive (doesn’t change the handset) and is corded.
Why corded? Partially because it’s cheaper, partially because it’s interesting looking, and also because, at least to my ears, the sound quality is better.
Bluetooth and cell phones are a marvel of miniaturization. Remember what cell phones looked like a decade ago? They were almost as large as the communicators from the original “Star Trek” series (which ironically was set in the 23rd century.) Miniaturization results in compromises. The current technology for tiny speakers and microphones is pretty amazing, but the quality sometimes leaves a lot to be desired. When I use my cell phone at home I usually hook it up to a repurposed pair of computer speakers to make it easier to understand conversations. So using an old corded handset with your cell phone may result in better voice quality.
In addition Bell Labs put a lot of research into design ergonomics for telephones. They’re designed to be comfortable (within the technology limitations of the time and given that they had to be produced for a reasonable price). Some people actually prefer using a standard phone handset instead of holding a cell phone up to the ear, having a Bluetooth unit stuck inside the ear, or wearing a headset. Unfortunately ergonomics design seems to have been forgotten in today’s cell phones. (What in the heck was Samsung thinking when they placed the far too low volume speaker on the back of my phone facing away from my ear?)
You had me at, well, the thought of walking down the street talking on this kind of handset... Forget the bluetooth borg drones, THIS is the way to chat on a cell! LOL