Description of problem:

I have a USB US Robotics modem - a real one that connects to wired phone lines.  It appears that modem-manager is trying to manage it, but this is not a wireless modem, so it is not doing anything useful, and is preventing me from using, e.g., wvdial.

Version-Release number of selected component (if applicable):

0.2 (from yum info ModemManager)

How reproducible:

Always (with this hardware)

Steps to Reproduce:
1. Connect USB US Robotics modem
2. Try to use wvdial
3.
  
Actual results:

--- /var/log/messages

Dec  8 14:59:03 idefix kernel: usb 1-5: new high speed USB device using ehci_hcd and address 5
Dec  8 14:59:03 idefix kernel: usb 1-5: New USB device found, idVendor=0baf, idProduct=0303
Dec  8 14:59:03 idefix kernel: usb 1-5: New USB device strings: Mfr=1, Product=2, SerialNumber=10
Dec  8 14:59:03 idefix kernel: usb 1-5: Product: USB Modem
Dec  8 14:59:03 idefix kernel: usb 1-5: Manufacturer: U.S.Robotics
Dec  8 14:59:03 idefix kernel: usb 1-5: SerialNumber: 0000002
Dec  8 14:59:03 idefix kernel: usb 1-5: configuration #2 chosen from 1 choice
Dec  8 14:59:03 idefix kernel: cdc_acm 1-5:2.0: ttyACM2: USB ACM device
Dec  8 14:59:03 idefix modem-manager: (ttyACM2) opening serial device...

idefix 102> wvdial
--> WvDial: Internet dialer version 1.60
--> Cannot open /dev/ttyACM2: Device or resource busy
--> Cannot open /dev/ttyACM2: Device or resource busy
--> Cannot open /dev/ttyACM2: Device or resource busy

Expected results:

wvdial dials and opens a connection

Additional info:

A workaround should be to disable modem-manager, but I can't even figure out how to do that.