How can I limit internet acess at certain times of the day?

[#1]

Hi,
Sorry - new to the forum and you've probably been asked the same question 1000000 times.
I want to limit internet access at certain times of the day to focus my son's mind away from his X-Box and onto his studies. Can someone please help me to do this? I'm not bothered if all internet access is lost for the time or if it is just X-Box access to the net.
Thanks.....jfk 

[#2]

Unplug the router and keep it with you!... 
keep the xbox in a locked cupboard. until you want to let him have it !. 

[#3]

Some sort of parental control software is probably needed for that, but for your purposes it would have to be on the router to avoid the restriction being bypassed. I don't think the Thomson TG585v7 has time-based parental control but potentially could be manually set to allow connection only to one website when you want to restrict access; the settings would have to be manually changed to open it up when appropriate. Not ideal but a start.