I broke my old Prolink Modem by walking around while it was plugged in and twisting the USB plug. I got a newer 7.2MB capable modem from Deal Extreme. Plugged into the beagleboard it shows up as a CD as expected and I ejected it to get the ttyUSBx devices. Unfortunately on the first try none of them wanted to respond to AT commands, it only started working after I installed the driver on windows and connected it up. A throughput test shows that it is working slightly better than the 3.6Mb/s Prolink promises.
Usual diagonistics on Linux shows:
lsusb - 05c6:0015 Qualcomm, Inc.
ATQ command works and dialing proceeds then I get stuck in an Unsolicited Message Block ("+ZUSIMR:2") using the ModemManager/NetworkManager Combo.
Manufacturer: BMC INCORPORATED
Revision: W1MV1.0.0B20100128 W1MV1.0.0B20100128 1 [Sep 4 2008 12:00:00]
Not much but at least a start for digging.