Having looked up Ambit and Conexant, there's pretty good odds this is a winmodem. I can't find out for certain without a lot of details. Winmodems use the processor to reproduce ring tones from the phone, and take special, almost always proprietary drivers to function properly. This is probably more headache than its worth. I use 'probably' instead of 'definately' because one day, bored over Christmas, I got the Lucent winmodem in my Thinkpad to work in about half an hour. PCMCIA modem cards are relatively cheap, and quite a few of them are supported under Linux.
Okay, if you want to try this one, you need to find out the exact model number of that thing because Conexant has made more modems than Hostess has produced Twinkees. Check Sony's online database about the VIAO. Also, from a command-line on the Viao, cat /proc/pci and a lot of the info on the modem should be listed (although this wasn't much help for me. I had to use IBM's site). lspci should do the same thing, but usually gives a little less vendor info. Then. with the model number, check through conexant's website DB (if they have one, which they should, unless they're real twerps), and most importantly: www.google.com/linux