Packrat, yes, the hand mic I am using on the 718 is an impedance mic, but I've seen where quite a few MD-1's are wired to the 718 with very good results.
Sonwatcher, thanks for the info. If I'm understanding your pin placement, the only wires that need to be changed are 1, 5, & 6 on the Icom side of the pigtail going into the radio????