Manufactured by Olivetti (AT&T acquired a stake in Olivetti in 1983, thus becoming a subsidiary) the AT&T 6310 compact electronic typewriter is a re-branded variant (I think) of the Olivetti CT-605 …
According to ribbon listings the following Olivetti-derived AT&T models were available:
AT-30, 5300 (Portable), 6100, 6110, 6200, 6210, 6300, 6310, 6400, 6500, 6510, 6610, 6710, 7500, 7500S, 7510, 7510S
Electronic Typewriter Instruction Guides
The following guide is viewable online and is freely shared. A small donation, however, will make it easier for me to continue to add to this archive. If you have donated, a printable copy of the PDF will be made available to you on request. Thank you!