This page will try to explain my experience with jtag cable.
Currently supported jtag utility is UrJTAG
apt-get install libreadline-dev
svn co https://urjtag.svn.sourceforge.net/svnroot/urjtag/trunk urjtag cd unrjtag
cd include ./autogen.sh sudo make install cd ..
cd jtag ./autogen.sh make make install
modprobe ppdev
$ jtag jtag> cable ppdev /dev/parport0 WIGGLER Initializing Macraigor Wiggler JTAG Cable on ppdev port /dev/parport0 jtag> detect