It may be that the TT connection doesn't need any login details.
That is exactly the case.
Attached, below, is a screen-scrape of how I set up a
Huawei HG612 for use with my
TalkTalk service. Although my official login name is
01284nnnnnn@talktalk.net (where the
nnnnnn is the final six digits of my telephone number) with a password consisting of various letters and digits, I routinely insert
burakkucat and
dummydummy into the two relevant fields.
