ADSL Connection prob

I am setting up a network of about 80 clients. However, i have just installed the first 18 pcs's to my switch. the switch is connected to the modem from my service provide.now the problem is that at times i have no connection, which can last for about 2-3 hrs. the bandith i have is 512/256 which i think it is very enough.But sometimes also, i connect one pc to the modem and it has connection and at time no connection. so i was wondering what the problem could be and how i can resolve it.please me me out.

If you are getting intermittent service with just one PC directly connected to the modem then logically it is not your network or switch that is causing the trouble. Review all the settings on your modem, check the physical cabling from the modem to the line, and ask your service provider to check both the physical line and your DSL provision. Often a poor physical line can cause the DSL to be intermittent. You couls also try connecting just a simple telephone to the line. If you hear crackling etc or the DSL 'whine' even when your microfilter is correctly connected that suggests a bad line too.
Let us know how you get on

I would probably try to rule out problems with your ISP or modem. When the problem re-occurs, first try restarting your modem.

If this does not work, try plugging a PC directly to the modem. Try at least two different PCs with different cables. If you still cannot access the internet, then you will probably need to take it up with your ISP.

oops! Sorry theBishop slipped in while I was writing my post!!!