Голосовой звонок через модем - чем ?

Не делал, даже не уверен, что это то, что нужно.
http://ofono.org/about

http://alsa.opensrc.org/index.php/FAQ

There is also another possibility. Maybe you have many devices that appear as soundcards. One of them may be a modem. Apparently, it can play stuff, but you probably won't hear anything and you certainly don't want to use a modem as the default soundcard. You can see whether this is your problem by examining /proc/asound/cards. See FAQ026 about how to change your default soundcard, or alias snd-modemmodule off in your /etc/modules.conf.

 Christoph Burger-Scheidlin added: You can refer to the cards by the name that is displayed in the /proc/asound/cards file. My /proc/asound/cards  file is...

0 [I82801DBICH4   ]: ICH4 - Intel 82801DB-ICH4
                     Intel 82801DB-ICH4 with AD1981B at 0x24000800, irq 11
1 [Modem          ]: ICH-MODEM - Intel 82801DB-ICH4 Modem
                     Intel 82801DB-ICH4 Modem at 0x1400, irq 11

and the respective entries in my /etc/asound.conf are:

# CARD DEFINITIONS
pcm.intel       { type hw; card I82801DBICH4 }
ctl.intel       { type hw; card I82801DBICH4 }

pcm.intelModem  { type hw; card Modem }
ctl.intelModem  { type hw; card Modem }

Посмотри также http://qtphone.sourceforge.net/

Насколько я понимаю, самым быстрым выходом будет винда в виртуалке с прокинутым USB ?