A strange dial-up issue…

Hello!

I am having a prblem with one of the computers I use. I have it connecting to the internet through an Earthlink dial-up account, and it is separated from the network. Unfortunately, the dialup connection has been doing some strange things. After dialing up, everything will be fine for several minutes. Then, out of the blue, transfers will simply end. It will not receive of send any data whatsoever. A few minutes later, it will work for another minute or two, and then go back to sending/receiving nothing. This goes on until I disconnect. The amount of time between changes varies, and there does not appear to be a pattern. I would much appreciate any insight as to the possible causes of this.

Most thankfully,
Luke