Something

span=2,0,0,esf,b8zs
fxols=25-28

span=1,1,0,esf,b8zs
bchan=1-11
dchan=24

defaultzone=us
loadzone=us

-----------------------
[channels]
 switchtype=national
 context=POTS-Incoming
 signalling=pri_cpe
 echocancel=yes
 callerid=asreceived
 group=1
 channel => 1-11

 signalling=fxo_ls
 context=faxhandler
 faxdetect=both
 echocancel=no
 channel => 25-28
---------------------
Zaptel Configuration
======================

SPAN 1: ESF/B8ZS Build-out: 0 db (CSU)/0-133 feet (DSX-1)
SPAN 2: ESF/B8ZS Build-out: 0 db (CSU)/0-133 feet (DSX-1)

Channel map:

Channel 01: Individual Clear channel (Default) (Slaves: 01)
Channel 02: Individual Clear channel (Default) (Slaves: 02)
Channel 03: Individual Clear channel (Default) (Slaves: 03)
Channel 04: Individual Clear channel (Default) (Slaves: 04)
Channel 05: Individual Clear channel (Default) (Slaves: 05)
Channel 06: Individual Clear channel (Default) (Slaves: 06)
Channel 07: Individual Clear channel (Default) (Slaves: 07)
Channel 08: Individual Clear channel (Default) (Slaves: 08)
Channel 09: Individual Clear channel (Default) (Slaves: 09)
Channel 10: Individual Clear channel (Default) (Slaves: 10)
Channel 11: Individual Clear channel (Default) (Slaves: 11)
Channel 24: D-channel (Default) (Slaves: 24)
Channel 25: FXO Loopstart (Default) (Slaves: 25)
Channel 26: FXO Loopstart (Default) (Slaves: 26)
Channel 27: FXO Loopstart (Default) (Slaves: 27)
Channel 28: FXO Loopstart (Default) (Slaves: 28)

16 channels configured.