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DIY Lightweight Clearcom Headset

Last Updated: 05May05
Note: This guide was written after I had completed mine, so I do not have any in construction pictures. I have tried to describe things to the best of my ability, but when in doubt use a VOM.

1. Parts and Tools and Overview


The main component of the project is the Motorola Headst (part number 53863, I bought mine from Product Wizard). This headset is very comfortable for extended usage, allows the user to eat and drink while wearing it, and boasts a very sensitive microphone. The only hurtle with adapting this headset for use with clearcom systems is that the headset uses an electret condenser microphone, where clearcom typically uses a dynamic mic. We will be creating a powering ciruit that operates off of a 9v battery in order to accomodate this.

The cable that comes attached to the headset as original equipment is kind of short, so you'll need some 4 conductor wire to extend it with. I had this laying around.

One of the first things you may notice about a stock 53863 is that it does not have a 4-pin XLR connector on it like clearcom needs. I bought my connector from the folks at Markertek.

From Rat Shack: (1) 10 uF capacitor, (1) 2.2k resistor, (1) 9v battery cap with leads. I happened to have this stuff laying around.

Also, you need (1) 9v battery from the wireless mic recycle bin.

You will need a soldering iron, solder, shrink tubing, wire strippers, dikes, a third hand (probably), and some patience.

 

2. Extending the OEM cable

Cut off the crazy radio 2-pin connector. Remove some of the outer cable jacket. You will see what appears to be 3 wires. The 2 coloured wires (red and white, if I recall) are the leads to the speaker. That third wire (black jacket) is actually another 2 conductor cord. VERY CAREFULLY, remove some of this cable jacket. You will find 2 conductors inside. They are the terminals for the microphone. Use your 4-conductor cord to extend this to taste. You should probably write down what colours are what on the OEM cable, and what the colour relationship is between the OEM cable and your extended cable - particularly if your extension has different coloured wires in it.

 

3. Start adding the 4-pin XLR connector


The pinout of a clearcom headset (per epanorama.net) is as follows:

# Pin 1: mic common
# Pin 2: mic hot
# Pin 3: headphone common
# Pin 4: headphone hot

Put the back of the connector on the cable first. It would suck to finish this and then forget that part (I know). At this point, slip the leads of 9v battery cap in, so that your finish product might resemble the picture above. Go ahead and attach the headphone leads to pins 3 and 4. Thats the easy part. Now is where the fun really begins.

 

4. Wiring the condenser powering circuit and finishing up

This is the part where it gets tricky and you'll want to beat your face in out of frustration because electrical components are very, very small.

This is the circuit we will be using to power the electret condenser microphone - also from epanorama.net

The positive lead and ground lead are pins 2 and 1 respectively. Solder the mic ground lead and the negative battery lead to pin 1.

Solder the negative (unpolarised? - not the plus side) of the capacitor to pin 2. Bend the other lead of the cap almost straight up against the cap body. Attach to this the positive mic lead and one side of the resistor. Solder the other side of the resistor to the positive battery lead.

If you keep the leads on things only as long as they need to be, you should be able to close the xlr connector so that only the battery cap hangs out and the rest of the powering circuit is contained within the connector:

If all has gone well, your headset should now be clearcom ready. Just add a 9v battery and you should be good to go.


I tested this bad boy out and it works great. Everyone can hear you very clearly from whispering to speaking normally to almost shouting. The earpiece is also very clean sounding compared to other headsets I've used. Additionally, the mic is out of your face, so you can eat and drink with it on. =) Enjoy

 

5. Change Log

05May05 - Corrected error on Plantronics m130 appendix.

25March05 - Added addendum for Plantronics m130 variation.

08March05 - Corrected error on parts list.