Is this compatible with Talktalk?
This feedback seems to suggest not
"Swapped ISP recently from BT to TalkTalk, unfortunately TalkTalk use PPPoA and this modem doesn't work with it."
OCE_Michelle's link will give you some settings that you need to note down.
I know that the DM200 has an option in Manual setup that asks if your ISP needs a username & password to connect because we had one at the office a while back (you'll need to select No).
I afraid don't know about what protocols it can handle though.