This is a fork of the osmocom libtelnet fork used to talk to ip.access NanoBTS devices' DMI debug console.
See this page on the Osmocom wiki for more info.
Of note: this doesn't appear to work with my pair of NanoBTS 165G models.
ipaccess-auth.c expects a challenge that's wrapped with <> characters, like this:
<xxxxxxxxxxxxxxxx>
But the challenge my units provide is wrapped in braces {} like this:
{xxxxxxxxxxxxxxxx}
I assume this is because the authentication mechanism in the firmware changed somewhere along the way; the braces might indicate a different algorithm is used, or possibly just a different key? not sure, and I don't have a live commercial installation I can sniff packets on :(