Hope it is helpful for somebody having same interests as me to install such winmodem under knoppix.

I had similar experience before to install a winmodem HSP56k under Red Hat 9.0. As a result , I already had the idea what I should do this time.

1. I checked my modem under windows. My machine is Dell Latitude C610, it has PCTEL 2304wt v.92 MDC.

2, I went to google to search pctel driver for Linux and found pctel-0.9.6.tar.gz. There is a newer version of it, but its configure program stucked when I tried to install it.
Follow link http://www.linmodems.org/
find link for download site for PCtel : http://linmodems.technion.ac.il/pctel-linux/

3. untar the downloaded package, then compile pctel modules

knoppix@ttyp0[pctel-0.9.6]$ ./configure
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for gawk... gawk
checking whether make sets ${MAKE}... yes
You should specify a target HAL.
Use './configure --with-hal=list' to see the HALs list.

knoppix@ttyp0[pctel-0.9.6]$ ./configure --with-hal=list
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for gawk... gawk
checking whether make sets ${MAKE}... yes
checking build driver for... available HALs are:
pct789, cm8738, i8xx, sis, via686a.

$ ./configure --with-hal=i8xx

$ make
knoppix@ttyp0[pctel-0.9.6]$ cd modules/
knoppix@ttyp0[modules]$ ls
Makefile Makefile.am Makefile.in pctel.o ptserial.o
knoppix@ttyp0[modules]$ lsmod

4: install modem modules
knoppix@ttyp0[modules]$ su
root@ttyp0[modules]# ls
Makefile Makefile.am Makefile.in pctel.o ptserial.o


root@ttyp0[modules]# insmod -f pctel.o
Warning: loading pctel.o will taint the kernel: non-GPL license - GPL linked with proprietary libraries
See http://www.tux.org/lkml/#export-tainted for information about tainted modules
Warning: loading pctel.o will taint the kernel: forced load
Module pctel loaded, with warnings
root@ttyp0[modules]# insmod -f ptserial.o country_code=6
Warning: loading ptserial.o will taint the kernel: non-GPL license - GPL linked with proprietary libraries
See http://www.tux.org/lkml/#export-tainted for information about tainted modules
Warning: loading ptserial.o will taint the kernel: forced load
Module ptserial loaded, with warnings

5. create link from /dev/pctel to /dev/modem

root@ttyp0[modules]# mknod /dev/pctel c 62 79
root@ttyp0[modules]# ln -s /dev/pctel /dev/modem
root@ttyp0[modules]# ln -s /dev/pctel /dev/ttyS15
root@ttyp0[modules]# chgrp uucp /dev/pctel
root@ttyp0[modules]# chmod 666 /dev/pctel

6. invoke Kppp to use /dev/modem , and fill in ISP tel no, user name plus password
Qery modem first to make sure the modem works properly