/etc/zaptel.conf

loadzone=de
defaultzone=de
span=1,1,3,ccs,ami
bchan=1-2
dchan=3
span=2,1,3,ccs,ami
bchan=4-5
dchan=6

/etc/asterisk/zapata.conf

[channels]

;erste Karte TE-Modus
switchtype = euroisdn
signalling = bri_cpe_ptmp
usecallerid = yes
overlapdial = no
immediate = no
group = 1
context = isdn_incoming
channel => 1-2

;zweite Karte NT-Modus
switchtype = euroisdn
signalling = bri_net_ptmp
overlapdial = yes
immediate = no
group = 2
context = default
channel => 4-5

/etc/asterisk/extensions.conf

[general]
static=yes
writeprotect=no

[default]
include => sip20
include => sip21
include => isdn_outgoing

[sip20]
exten => 20,1,Dial(SIP/20,25,tT)
exten => 20,n,Hangup

[sip21]
exten => 21,1,Dial(SIP/21,25,tT)
exten => 21,n,Hangup

[isdn_incoming]
exten => 12352,1,Dial(ZAP/g2/52)
exten => 12352,n,Hangup

exten => 12353,1,Dial(SIP/20,25,tT)
exten => 12353,n,Hangup

[isdn_outgoing]
exten => _7.,1,SetCallerID(12352)
exten => _7.,n,Dial(ZAP/g1/${EXTEN:1})
exten => _7.,n,Hangup