As for Huawei HG850a, this will not work because TM has firewall(iptables) enabled to block access from local LAN port...

1) Set your local ip to 192.168.1.XXX/24
2) Connect to any local LAN port
3) Power Off/On HG850a
4) Keep refreshing your browser on http://192.168.1.1

you should able to view the web access login page for seconds before firewall is loaded then there goes our webpage/ssh(or was it telnet i forgotten about it)...