(Using Trixbox to try and get a 'known good' Asterisk config, so I make as few mistakes as possible before transferring the eventually working setup to my production box!)

[trixbox1.localdomain asterisk]# cat /etc/zaptel.conf

fxoks=1-24

[trixbox1.localdomain asterisk]# cat /etc/asterisk/zapata.conf

[channels]
group=1
signalling=fxo_ks
context=jmh
channel => 1-24