Here's one that drives people nuts. SB and BB IAC are wired differently.
Wiring:
SBC Connector
IAC Plug
A ~11.86 v Lt Blue/White Stripe A Hi
B ~.452 v Lt Blue/Black Stripe A Low
C ~11.86 v Green/White Stripe B Hi
D ~.453 v Green/Black Stripe B Low
BBC Connector
IAC Plug
A ~452 v Green/Black Stripe B Low
B ~11.84 v Green/White Stripe B Hi
C ~.452 v Lt Blue/Black Stripe A Low
D ~11.84 v Lt Blue/White Stripe A Hi
