Hello, because this is old threat, you probably have a solution yet but I have similar problem, Internet works for about 30 minutes and then modem lost connection and try to reconnect itself. I have TD-W8951NB. I today probably solve this problem by deactivating all Virtual circuits except Virtual circuit which is used to internet connection. Problem of disconnecting is now probably solved, maybe it will happen again, but it's running now for about 7 hours and it still wasn't disconnected. Modems log still say that there is some error, but that error, which probably cause disconnecting there isn't and modem simply works well. Maybe you have something else with modem, but I just share my experience and hope, that it will help someone else who have same problem. Also excuse my bad English, it isn't my native language and I cannot speak it well. PS: I also manually set up modulation to G.DMT but modem previously detect that too and use it, so as I said, i think it is caused by too many activated Virtual circuits.