This is Zapata.conf

[channels]
context = from-pstn
switchtype = national
usecallerid = yes
echocancel = yes
echocancelwhenbridged = yes
rxgain = 0.0
txgain = 0.0

signalling = fxs_ks
group = 1
channel = 1-2

signalling = pri_cpe
group = 0
channel = 25-48

signalling = pri_cpe
group = 1
channel = 49-71

---------

zaptel.conf below

  GNU nano 1.2.4                                                                             File: zaptel.conf

loadzone = us
defaultzone = us

#analog init
fxsks = 1-2

#span definitions
span = 2,1,0,esf,b8zs
span = 3,1,0,esf,b8zs

#chan defs
bchan = 25-47,49-71
dchan = 48-71