ModemLockDown for Windows

The description of ModemLockDown - Play With New Friends

ModemLockDown automatically disables Internet use until a supervisor or parent is present to grant access. You can pre-allocate automatic one-hour access blocks for individual users or permit access with limited or unrestricted time. Dialup modems are locked to halt malicious dialling. This can occur automatically when you disconnect your session. Supports Dialup, DSL\Cable, XP, Vista & Windows 7.