10 years ago
  USRobotics (Modem/Router/Wireless router/Switch)
  Mint (older version)
  Works perfectly
What works:

The 56k USB modem works fine and no extra drivers are required.

What was done to make it work:

To get a usb modem to work with Helena yo uhave to remove the "modem manager" - this package is used for 3G modems as far as I'm aware and conflicts with usb dial-up modems.