Telephone RJ-11 adapter for Headset Mic?

Archived from groups: rec.audio.pro (More info?)

<briglass@gmail.com> wrote:
>I have a headset microphone with two 3.5 mm input/output mini-plugs (or
>two 1/4" (6.3 mm) phone plug adapters). Is there any way at all that I
>could use this with a regular phone (RJ-11)?

Probably not. Note that the handset jack on a regular telephone is not
an RJ-11 at all, but is narrower.

Telephone sets generally expect to see a carbon button microphone and
a 600 ohm earpiece. It's possible to build electronics to make an
electret capsule behave like a carbon button, but that's what keeps
Plantronics in business.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

Bob Ross <bross@berklee.net> wrote:
>Scott Dorsey wrote:
>> <briglass@gmail.com> wrote:
>> >I have a headset microphone with two 3.5 mm input/output mini-plugs (or
>> >two 1/4" (6.3 mm) phone plug adapters). Is there any way at all that I
>> >could use this with a regular phone (RJ-11)?
>>
>> Probably not. Note that the handset jack on a regular telephone is not
>> an RJ-11 at all, but is narrower.
>>
>> Telephone sets generally expect to see a carbon button microphone and
>> a 600 ohm earpiece. It's possible to build electronics to make an
>> electret capsule behave like a carbon button, but that's what keeps
>> Plantronics in business.
>
>Eric Small once built me a Telephone to Line Level adapter that
>consisted entirely of an RJ-whatever jack for input, a tiny
>transformer, and an 1/8" TS jack for output. I used it for years to
>record over the phone lines: Instead of trying to cobble together a
>fake (cliched) "telephone sound" for low-fi vocals or drums, I would
>literally record them over the phone. Way cool. Unfortunately Eric's
>box disappeared before I got curious enough to determine what sort of
>transformer it was.

It was a 600-600 ohm one, probably a "wet transformer" designed to
handle the DC current across the line. Tamura makes a bunch of decent
ones that Digi-Key has for a couple bucks each.

Getting signal out is easy, the problem is the microphone side.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."