@VoiceInMyHead, glad I could help and thank you for the Kudo.
Some of us should get paid by Optus as we are often better than them at finding answers and resolving problems that even moderators can't fix ;-)
I have just found an answer to a problem that has taken Optus more than a year and a half to NOT give us any feedback or fix it. I will be posting the answer on the Forum soon.
At time of writing, 8PTu5W@C is the default admin password for the Optus-supplied, Sagemcom F@ST 3864AC Gateway v2 (black).
There are two levels of admin access on the Sagemcom F@ST 3864AC gateway however; user-level admin and full admin. Accessing the gateway through 192.168.0.1, even when using the username "admin", will only provide user-level admin access and a reduced set of options will be shown under the advanced settings tab.
The full admin interface with extended configuration options needs to be accessed through its full url of 192.168.0.1/main.html.
YES! This!! I also have the Sagemcom 3864V3 and have been searching for the login details. Thank you so much!
Password: provided WiFi password (mine came on a handy little fridge magnet about the size of a credit card)
Thank you!! This worked after trying all the other options.
password: the wifi password on the Optus business card magnet supplied with the modem
I recently took someone's advice on this forum. They said "it should be on the bottom of the router/modem"
Look for "Username" and "WPA Passphrase". Usually username is "optus" and passphrase is your default internet password.
I hope this helped.