Dialup accounts are designed to be used by people, not machines. The connection should be dropped when it's not actually in use.

It is not permissible to tie up a phone line continuously. Connections that remain up 24x7 may be terminated.

We don't probe to for violations, but if we notice this sort of usage we will investigate and are likely to terminate the connection. Users who persist in this behavior after receiving a warning may be subject to account termination without notice or refund.