[Yaesu] Voice Synthesiser FVS-1A

[Deon Erwin ZS1ZL]

I advised my blind ham friend to buy an FT-847 for the voice synthesiser
option it offers for blind operators.  As the radio is no longer produced, a
local Yaesu dealer sold him an FT-857D with the assurance that the FVS-1A
voice synthesiser unit of the FT-847 can be installed in the FT-857/FT-897
transceivers.

The FT-847 has a dedicated button with an embossed "V" so that a blind
person can operate the voice synthesiser.  The FT-857D has no such control
button and I cannot imagine how a blind person would operate a voice
synthesiser in this radio.

I consulted the FT-857D operating manual and the technical reference and
cannot find any reference to the installation of a voice synthesiser.

Now I turn to the members of this forum:

*  Can the FVS-1A be instaled in the FT-857D?
*  If not the FVS-1A, is there another voice synthesiser for the FT-857D?
*  If a voice synthesiser can be installed, how is it operated without a
   control button?

Your assistance will be appreciated.

Regards
Deon ZS1ZL