zapata.conf:

[channels]

signalling = fxo_ks 
language = en
context = zap
immediate = no
channel => 1

signalling = fxs_ks 
language = en 
context = zap
channel => 4

extensions.conf:
[zap]
exten s,1,Answer()
exten s,2,Background(tt-monkeysintro)

exten 2,1,Background(tt-monkeys)