[ICOM] CI-V from USB - schematic ?

[Jim Miller KG0KP]

Seems like if a ci-v is only 2 contacts that I can make one from one a USB 
to DB9 connector with an adapter or a pair of dikes and a mono plug ????????

Comments ?

I have a 705 MkIIG and it appears the CI-V is not functioning.  What is the 
SIMPLEST way to test it?  I have tried 3 USB CI-V cables.  I have tried 
another laptop.  No go.  I found another cable that is DB9 to mono plug but 
am not sure it is a ci-v cable.  Likely?  Comments?

Thanks es 73, de Jim KG0KP