I heard the foxwell nt510 can read e30/e36s that were ADS only, Then I saw they have an adapter on sale that looks like this:

Foxwell's a chinese company and often these chinese companies optimise the hell out of their products to make them the cheapest (almost to a fault as we all know), I can't think of any reason they'd make the port 20pin > serial rather than a straight 20pin > 16pin? Does this interface the ADS to an 16pin connector? If it had no function they wouldn't waste their time on it and I know this is specifically to use on e30/e36 pre 98 bmws.