EDIT:
SOLVEDEDIT: it seems firmware 5.11(AAXA.3)C0 increased the character limit. The release notes only mention support for a wider range of special characters, but I just tried it anyway. Hopefully I'll be able to get this configured properly now
I bought a used ZyXEL VMG1312-B10D via eBay. It appears to be from Zen, but as far as I can tell it seems to be working just fine.
However I don't think I can configure it to connect to my ISP? The problem is I can't write the ISP's username in the PPP username field (screenshot attached) as there is a maximum limit of 32 characters, but the ISP username is 37 characters.
Does this mean the ZyXEL is rendered useless for my connection?
I'll try updating the firmware but I can't see anything in the release notes about it.