Hi,
I think none. RC 1216H talks serial, so you would need a converter between.
Like GS-232B (?) or some third party control card (like ERC). The card could be installed inside
the control box in parallel to the manual pushbuttons, unless you buy a bigger yaesu, that has a mini-DIN
connector giving out the necessary signals for the card.
WebSwith 1216H & RCL 1216L might do that as well.
Joni OH2FT