Few days ago I bought a brand-new Zakang ZX-400 phone, from a local CDMA Operator, Unite
Also, I have opted for a monthly subscription, including unlimited internet access.
The main issue is that they provide drivers/instructions for WinXP/2000, and I'm not going to use Windows just because of this :)

Ok, I plugged it in...

kernel: cdc_acm 1-1:1.0: ttyACM0: USB ACM device kernel: usbcore: registered new driver cdc_acm kernel: drivers/usb/class/cdc-acm.c: v0.25:USB Abstract Control Model driver for USB modems and ISDN adapters

It looks like a standard acm modem.
Let's try to use it with wvdial

apt-get install wvdial
nano /etc/wvdial.conf
[Dialer Defaults]
Phone =
Username =
Password =
New PPPD = yes

[Dialer unite]
Modem = /dev/ttyACM0
Baud = 230400
Phone = #777
Init1 = ATZ
Stupid Mode = 1
Dial Command = ATDT
Username = net
Password = rapido
PPPD Options = crtcts multilink usepeerdns lock defaultroute

Then start it:

wvdial unite

After a few debugging messages, the connection is up! ;)