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.

Let me state it again since some folks have ignored it in the comments. I am NOT providing a specific schematic, details on the connector for any particular phone, or more details on how to hook this up. It is an extremely simple circuit if you've got the right skills and knowledge and the ability to use a search engine to look up the details for your particular phone and verify that it'll work with whatever handset you can get your hands on. DO NOT ASK!

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.

Step 1: why a corded handset

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?)

The specific description in this tutorial is for a phone with a four conductor (TRRS) 3.5 mm. mini jack which is used for stereo audio output and mono mike input, commonly found on many iPhones and Androids. If you want to build this adapter it’s your responsibility to make sure that this is the correct connector for your phone, or what plug is required and its pinouts and wiring diagram for your particular phone.

For example, here’s how somebody wired an older cell phone which uses a 2.5 mm (micro mini plug) with three conductors instead of four.

In addition telephone handsets have evolved over time. The original carbon microphones have been replaced with electret mikes. In some cases telephone handsets are not interchangable because the manufacturer used a special microphone in the handset and the circuit in the phone which encodes the voice is designed to work with that microphone.
<p>میتوان باهاش راحت صحبت کرد اما یک سوال،اینکه کیفیت صدا خوب هست یا نه؟</p>
This is great instructables, I'm attempting to do the same thing but i'd like not to rip off one working handsfree headset, so i'm looking for the 3.5&quot; jack with 4 poles for now with no luck at all. <br>So my question is: because the old fashioned headset is not stereo (is it?!) can i use a 3 poles jack excluding one of the two line out and make it mono instead of stereo?
what would happen if you attached this to a usb cable and plugged it in
It would probably explode and the sun would go supernova. I wouldn't recommend doing it.<br>
Attention, not all mobile phones have the same connection.<br><br>The links can be found here.<br>http://pinoutsguide.com/pin_HeadsetsHeadphones.shtml
This is great stuff. I myself would gladly use such thing. I would look like a cool guy :) Can you please give a more detailed schematics of all the wire connections???
See my response to a previous comment for why I am not including more detailed schematics. If you want to build it - you've got to do the research for your phone.<br>
Thank you!
Old phones use Carbon microphone. <br>You have to add battery and resistor to make this working...<br>VCC----------+ <br> |<br> -<br> | |<br> | | Resistor<br> |_|<br> |<br>SIGNAL-------+ <br> | <br> | <br> Carbon <br> Microphone <br>GND----------+
brothers plz give me the details about HEADSET MODULAR JACK....is it has any circuit diagram..?
See my response to a previous comment for why I am not including more detailed schematics. If you want to build it - you've got to do the research for your phone.<br>
is the signal strength of the typical cell phone headset output strong enough to drive the speaker on the handset? seems like it would be somewhat quiet.
What's a typical cell phone headset?<br><br>On my old Nokia 5320 the volume level was excellent. On the crappy (expletive deleted) Samsung Android shown in the photos it wasn't so hot. The Nokia had excellent volume and voice quality to begin with, the Samsung had rotten voice quality. So I suspect it depends on how decent your audio from your cell phone sounds to begin with since it's driving the speaker.<br>
I love it!
I am a ludite ;0) I like it :0)!
plz give the circuit diagram of headset modular jack........
Oh man, this is awesome. Maybe a close-up picture of where you attached the wires would clear up any question about how tuff gets attached. I was slightly confused until I re-read the instructions a few times. I really want to expand this into something more....
I intentionally left out a closeup photo of the connections for my particular phone because I didn't want somebody to think that it was how they should wire their own phone. There are *lots* of variations and as I noted in the introduction anybody who wants to make one is responsible for doing their research.<br>
Ok, duly noted.
I love this. I've seen commercial versions but it's so much cooler to make your own. Best yet is talking to your pocket in the mall. Nice.
What a great idea! I've been thinking about doing something like this with an old-school headset with microphone... This has some great potential for Steampunk/Dieselpunk cellphone accessories... If the star rating feature was working, I'd give you 5 stars!;-)
Truly a hipsters dream!<br>That's quite creative, sir.

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