Andy, thank you , thank you...now I have to back to the books to
understand what you told me to do.... ;-) LOL thanks again.

WA3LTJ wrote:
LC wrote:

I am trying to incorporate a mobile CB Midland 13-857 to my
motorcyle, I need to know how to add a circuit to the input (mic)
so
I can use a head set. I can hear and currently use the hand mic
when
riding... (the head set came from a computer with two jacks, one
for
speaker and one for mic).... can it be done? Can anyone help?

thanks Ken

It can be done.

You need do:
1) match the pin wiring
2) match the microphone impedances (although this may not be
important)
3) match the gain of the microphones with an attenuator or amplifier.
4) supply power to the computer microphone if it is an electret type.


You will need to get the microphone connector wiring from the manual
or
from opening the microphone. If your computer microphone is electret,
it will need 3 to 12 volts of DC to operate the element. I don't know
if CB manfacturers put a voltage like this on the microphone
connector.

Anyway, it is not straightforward, but it can be done. I did it for
my
Midland 2 meter rig. I embeded a speaker and tiny electret mic in the
foam of my helmet.

Andy