Another package arrived!
This is a straight through 1-1 pin for pin cable. It's important to order explicitly extension cables labelled as being for a purpose that uses all the pins. If they're a true extension cable, they'll have all the pins wires straight through one-to-one, with no strange interconnects or permutations or omissions. I couldn't use either of the cables I ordered if they didn't have all the pins linked to wires. This was labelled as being a serial cable extension: you could use it to lengthen your serial port, but it is not a nullmodem cable so no Dukematches for me.