clothes washer

So clearly from what we can see here this does not appear to be compliant, what gives be pause is the fact that the connections for the clothes washers are not trapped, makes me wonder if perhaps there is a trap and vent below grade, if that were the case, would this be any different than...

Please forgive the ignorance that I have about plumbing. I look forward to learning from you. I own a house built in the 1950s. It would appear a past owner tapped a washer drain pipe into some existing water pipe. That water pipe is MUCH smaller than normal. I think a plumber has said maybe...