Modem refuses to establish a direct connection.
That's not possible if it's a pure modem with no router functionality as I mentioned previously. Any chance you can get us pictures of the modem?
You must purchase a separate router.
I located the modem, it's an ARIS TM106. It was a replacement we had, and apparently it got damaged during a thunderstorm.
Was das 1602 gemeint? Hier ist der Link: https://www.arris.com/globalassets/resou...eet-v2.pdf