Zaptel.conf
-------------------------
loadzone        = us
defaultzone     = us
span=1,1,0,esf,b8zs
bchan=1-23
dchan=24

zapata.conf
-------------------------
signalling=pri_cpe
switchtype=national
echocancel=yes
echocancelwhenbridged=yes
callerid=asreceived
group = 0
context=incoming
channel => 1-23