1) Download Zaptel (the kernel modules)

   $ svn co http://svn.digium.com/svn/zaptel/branches/1.2 zaptel-1.2
   $ cd zaptel-1.2
   $ make
   $ sudo make install

2) Edit /etc/zaptel.conf

   Add the following lines to the bottom:

   fxsks=1
   fxoks=2-4

3) Load the modules

   $ sudo modprobe zaptel
   $ sudo modprobe wctdm
   $ ztcfg -vv

At this point, you should see output similar to this:

Configuration
======================

Channel map:

Channel 01: FXS Kewlstart (Default) (Slaves: 01)
Channel 02: FXO Kewlstart (Default) (Slaves: 02)
Channel 03: FXO Kewlstart (Default) (Slaves: 03)
Channel 04: FXO Kewlstart (Default) (Slaves: 04)

4 channels configured.