Acoustic coupler

Hello,

i'm working on a Speechrecognition project with Arduino and EasyVR Modul 
(VeeAR).

All works perfect when i bring a dictaphone speaker near to the EasVR- 
modules microphone.

Now i want to substituate the speaker and the microphone
by some electronic parts similar as a optocoupler or
transformator but i have no idea how to and not a lot of psace
to place big part..

How can i connect the dictaphone output signal directly to
the microphone input ?  (without burning the DSP-chip.

Maybe a simple RC circuit is sufficient (?) but first trials
fails.

Any idea or hint highly welcome.

wally