Airtel Broadband

I have Airtel broadband with land-line. Without connecting telephone line to broadband router, my telephone works properly. But when I connect tel line to router, my internet stops working and my telephone lines incoming call stops.But if I connect tel line directly to router and tel line is disconnected internet works properly. But that time also incoming calls stop working. I have Beetel 450BXI router. I can not use broadband and telephone at the same time now. What would be a problem? Is it connectivity prob at airtel or it is router prob? please help..

If you are having a broadband connection then there should be a splitter, here the splitter is separate for both broad band and the phone traffic and it should be installed at the point where the connection enters your house, the splitter should be connected to the phone-line directly and after that you should have one connection to your phone and other to router/modem, so just check out if this connection is proper or not, if you are not bale to find out the exact cause of the issue then you should better contact the isp, they will surely help you out with it.

Thanks Carita
I have checked splitter by replacing other one. Splitter does not have any problem. What is isp?