My ADSL Modem Restart itself

I think it's because of electricity problem. Please check your wall outlet voltage, if you think the voltage on your wall outlet is ok, so please check the output voltage from electric adapter that attach to your ADSL modem.

There might be a problem with your modem's firmware. It would be much better if you call your internet service provider and tell them what's wrong with your modem.

Hi, you should tell us what kind of modem/router is,if it's new or old,a model,a name,something :) However,it seems to be a firmware problem,many Zyxel routers has it for example. You should go to the manufacturer site and check for upgrades.

Most of modern day electronic today have a fail safe system, is which if a system detect overheating on a certain part, it will try to reboot the unit, to protect it from reaching a critical temperature threshold to avoid damage. Try adding some fan, if the 1 - 3 hours restarting period increase, if not then move to another solution. Troubleshooting can be a teadious one.