I am running the following setup not from a distribution.
FreePBX: 2.11.0
Asterisk: 11.8.1
Dahdi: 2.9.0
Centos: 6.5
etc/dahdi/system.conf
span=1,0,0,CCS,HDB3,CRC4
span=2,0,0,CCS,HDB3,CRC4
bchan=1-15,17-31,32-46,48-62
dchan=16,47
I am using a Digium TE220 set for Europe.
/etc/modprobe.d/dahdi.conf
options wct4xxp default_linemode=e1
/etc/asterisk/chan_dahdi.conf
[channels]
language=en
busydetect=yes
busycount=10
usecallerid=yes
callwaiting=yes
usecallingpres=yes
threewaycalling=yes
transfer=yes
cancallforward=yes
callreturn=yes
echocancel=yes
echocancelwhenbridged=no
echotraining=no
immediate=no
faxdetect=no
rxgain=0.0
txgain=0.0