My problem was that while using the usr5610b it would take three tries at least to connect, then would not download mail from one of my three mail accounts - the one given free by the ISP.
I made the first line in /etc/rc.d/rc.serial read:
and on the first attempt it connected the way it should, and also downloaded all the mail including a test from that account.
My fingers are crossed.
Much thanks for the article.