The AR860 is shipped by e.g. versatel - configured as a DSL modem.

Admin accounts

Firmware b2

IP 150.150.150.4
Login admin
Password xad$l#12 (that's a lower case "L")

Firmware b3

IP 192.168.1.1 or 192.168.254.254
Login admin
Password Admin or xad$l#12

Convert to Router

To switch from "Modem" mode to "Router" mode, there's a nice manual over at versaforum.de. Another manual is at mhilfe.de.