As per my knowledge, even I have tried with D-Link Modem which was brought at Rs. 2100 from a dealer. It was very difficult to instal with VSNL software which was getting connection delayed. I think the problem must be in the telephone line but not in the modem. Now a days cable modems are comming which is giving a very good performance wherein their is no need for telephone connection, Only problem is we cannot chat.It is really telephone line which is giving much problem