I bought my cable from Johnstone, however I think the Johnstone
diagram has changed since I bought my cable as mine didn't come wired
that way (but close). Even so, mine did not work wired-as-arrived
with my Highway 100 converter, plus I have a thing about avoiding
ground loops, so I redid it as follows:
IIgs SCART
01 red gnd -> 13 red ground
02 red video -> 15 red video
05 grn video -> 11 grn video
08 +12v -> 16 RGB control via 270οΏ½
09 blu video -> 07 blu video
12 Cmp video -> 20 Cmp video
shield NC shield (shield wire attached at SCART end only)
This list of connections is the total connections list -- not a list
of changes. Note that I removed sound.