Won't work, Windows XP Fax only supports one modem:

http://members.shaw.ca/bsanders/FAQFAX.htm#_Toc88835153
23. What is the limit on the number of fax devices supported on different
Operating Systems?

Hal
--
Hal Hostetler, CPBE --
Senior Engineer/MIS -- MS MVP-Print/Imaging -- WA7BGX
http://www.kvoa.com -- "When News breaks, we fix it!"
KVOA Television, Tucson, AZ. NBC Channel 4
Live at Hot Licks - www.badnewsbluesband.com

"Nik" wrote in message
...
Hi all
we have a program that sends fax printing them on Microsoft fax
I can't modify anything in this program.
I was wondering this : it may be possible to mount 4 PCI modems in one
pc and use them to send faxes? I mean send 4 faxes on 4 lines in the
same moment.
Maybe that Microsoft fax itself "choose" which line use.

thanks
Nik