My first question (quoted here at bottom) was not about using normal stereo
headphones for speaking on the phone. Of course that wouldn't work, unless
you are just listening and not speaking, as normal music headphones don't
have microphones.

My first question concerned using a normal phone headset in the MpX200,
rather than the ones that come with it, for speaking on the telephone. A
normal phone headset does have a microphone, whether "in-line" or a boom,
and has a 2.5 plug, which would fit in the MPX200's 2.5 jack without an
adapter.

So, I would assume that that would probably work for telephony. (Although
not good for listening to music--monaural, etc.) But, I guess it's possible
that there is something so different about the wiring inside the jack of the
mpx200, that a different phone headset would not work in it, although the
plug would fit in the jack. Therefore, I wanted to know whether someone has
tried that.

Has no one reading here tried that-using a different phone headset with the
Mpx200, than the ones that come with it, for speaking on the phone?

with

calls?

headphones,