[1000mp] PTT keying current on FT1000MKV Field

[Mark]

In building a FSK interface for my FT1000MKV Field. I was having trouble 
with the PTT, the
FSK part worked fine.  What I found was that the PTT keying circuit of the 
FT1000 needed
a current sink of about 18ma which my poor little opto-isolator was not up 
to.  This was in
conflict with the ops manual which indicates a current sink requirement of 
1.5ma.

(The FSK needed less than .5 ma sink.)

Am I missing something?

Mark N2QT