A:
either modemor routers has a ip adresses 192.168.XXX.Xlike if u try to read or get online manuel it will give u access to hardware if its helps some how to get arround
other option if there are hard reset by the hardware you can so its start like brand new mostly admin/password is defoult
i dont know much but try to offer my guess its no relaible maybe but very common sense
im happy if it helps im sorry if nosense GOOD LUCK...