Computer Headset On Yaesu FT-857D

I had a computer headset with a boom mic that no longer worked. I think the small wires inside the molded plugs had broken.

I had always been impressed with the audio quality of these relatively cheap Logitech headphones and microphone. The mic naturally has a strong mid-range peak that I think lends itself very well to HF work and getting heard in a pile-up. But that’s just my theory.

I had been successful wiring up my Kenwood MC-50, using pinouts I found on the Internet. The mic jack for the FT-857 is an RJ-45. The pinout for the FT-857 is as follows:

1 – FAST Scan
2 – Ground
3 – PTT
4 – MIC +
5 – MIC Gndschematic
6 – +5 Volts DC
7 – Up
8 – Down

The tricky part is figuring out which pin is pin1!  I used an old CAT 5 network cable, and I used the following pins: 2, 3, 4, 5 and 6. On my cable, these were white/brown, green, white/blue, blue, and white/green. Color codes can vary, so double check.  If looking at the microphone jack directly,  pin 1 is all the way to the right.

The following site was very helpful to me in getting pin outs for Kenwood and Yaesu: G4WPW Microphone Connections

Here’s what I ended up doing and after a few HF contacts, and some on the local repeaters I’m convinced it works pretty well.



One thought on “Computer Headset On Yaesu FT-857D

  1. Les

    This is about the third version of a home brew interface to use PC headset on the 857D. The first i built, I cannot find the site for but it used a 470Uf electrolytic (parallel with mic) and 47Uf electrolytic (series with a 1K resistor in the mic + circuit) as filtering. It as well as the 2nd version use 4.7K ohm as current limiting resistors (in the +5 vdc ckt) where you use the 2.2K and both use .01Uf as isolation caps where you use the 10Uf electrolytic.

    I have used the first with a bit of success and it seems to provide a pretty nice audio that I found has a broader range than the oem mic. I have built the second to use in my car but have not used it so do not know how much the electrolytic caps and 1K resistor do as far as tuning the audio response.

    Does yours get any better audio reports than the oem hand mic or is it more tinny without any filtering as the PC headsets tend to do without some massaging?

    Yours is definately more simple than either of the interface circuits I have built so I may try it in a bit and do some on the air comparisons.

    Thanks for the info… – ac0hd


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