Asterisk externer Provider

/etc/asterisk/sip.conf

register => ZZZZZZ:YYYYY@sipgate.de/0123456789

[sipgate_incomming]
type=friend
context=default
host=sipgate.de

[sipgate_outgoing_account1]
type=friend
username=ZZZZZZ
fromuser=ZZZZZZ
fromdomain=sipgate.de
secret=YYYYY
host=sipgate.de
nat=yes
insecure=invite
qualify=yes
dtmfmode=rfc2833
disallow=all
allow=ulaw,alaw
outboundproxy=sipgate.de

/etc/asterisk/extensions.conf

exten => 1748852,1,Dial(SIP/0001) <-- statt Nebenstelle sollten Sie den entsprechenden Peer definieren
exten => 1748852,n,Hangup

exten => _XXXXX.,1,Set(CALLERID(num)=ZZZZZZ)
exten => _XXXXX.,2,Dial(SIP/sipgate_outgoing_account1/${EXTEN},30,trg)
exten => _XXXXX.,3,Hangup