Bước 1: Tạo password
echo -n "1234" | md5sum
outout gives : 81dc9bdb52d04dc20036dbd8313ed055
Bước 2: tạo file chứa password
vi /tmp/pin.txt
1000:81dc9bdb52d04dc20036dbd8313ed055
1001:81dc9bdb52d04dc20036dbd8313ed344
Bước 3: tạo ngữ cảnh gọi
vi /etc/extension.conf
[outgoing] exten => _X.,1,NoOP
exten => _X.,Authenticate(/tmp/pin.txt,am,4)
exten => _X.,Dial(DAHDI/g0/${EXTEN})
exten => _X.,Hangup