Try connecting with an external version of another brand modem and see if the problem disappears. Even if your modem connects perfectly to another provider, there might be a problem connecting that modem to the 1 Big Red. However, the 1 Big Red goes to great lengths to make its modem pools as highly compatible and reliable as possible. Initialization Parameters Certain features of modems are turned on and off by the initialization string used to wake up the modem before a call is made. Oftentimes, some of those configurable features can make a big difference in the quality of the resulting connection.
INIT strings can also turn on disconnect-avoiding options that are off by default.
If you suspect that line noise might be an issue, there might be an AT command for your modem that will tell it how long to wait before hanging up when it loses carrier detect. Making the modem wait longer before hanging up could prevent some disconnections. Check for this setting in your modem manual. In some cases, because of normal telephone line conditions, a high-speed connection might lead to an unexpected disconnect. Your V.34 or V.90 modem will try to connect at the highest speed possible.