Mike,
Yes, there is an error in the drawings.
On both FT-100 connectors Pin#4 should connect to TTL Pin#6 instead of Pin#1
Also on both units, Pin 1 of P5B (which is connected to TTL Pin#6) should have a jumper to "PWR SW" P5B Pin#9.
When those things are changed, the FT-100 seems to work very well.
Probably very few FT-100 users now, and of those, very few have the extender kit required.
I personally use several of these radios at remote locations, and I greatly appreciate your work on this radio.
Thanks again.
Steve, k5dog