[Yaesu] Standard mobile dualbnd model 5718

[Martyp]

I have mostly Yaesu  h.f. gear, but I own a Standard dual bander model 
C-5718 with the CMP control head. I am visually impaired and have installed 
the tranciever into my wife's car. My problem is how to get it to go from 
the outboard speaker mode to the one on the handhelp control head. If 
anyone can help my wife do this, I would appreciate it...when we moved, we 
lost the manual. Thanks in advance. I believe it was their last dual bander 
with 800-900+ mhz capabilities without modifiying it.

Kind regards,
Martin Jay Pearlman, W3QK