Can you decode this for me? :)

[phoneguy01]

Our usual asterisk guy is out sick. I'm trying to decipher exactly what these entries below mean. I understand some of it because it's obvious, but other parts I'm not so sure. If you can, would you please break this down for me and tell me what each entry is doing? I edited the real phone numbers and server names to protect the innocent . Also, if there's a document that describes all these parameters, could you point me to it please? Thanks

This is in our /etc/asterisk/extensions.conf file:
[default]
;Not Valid
exten => s,1,Playback(invalid)

exten => 12345,1,Dial(SIP/+15555512345@SERVERNAME,60,tr)
exten => 12345,2,Dial(SIP/+15555512345@SERVERNAME,60,tr)

exten => _XXXXXX,1,Dial(SIP/+${EXTEN}@SERVERNAME,130,tr)
;exten => _XXXXXX,2,Dial(SIP/+${EXTEN}@SERVERNAME,130,tr)

exten => _+1555.,1,AGI(2ldap.agi,tel:${CALLERID(num)},${EXTEN})
exten => _+1555.,2,Set(CALLERID(number)=${num})
exten => _+1555.,3,Dial(H323/9${EXTEN:5}@PBX,130,tr)

exten => _+1554.,1,AGI(2ldap.agi,tel:${CALLERID(num)},${EXTEN})
exten => _+1554.,2,Set(CALLERID(number)=${num})
exten => _+1554.,3,Dial(H323/9${EXTEN:2}@PBX,130,tr)

exten => _+1.,1,AGI(2ldap.agi,tel:${CALLERID(num)},${EXTEN})
exten => _+1.,2,Set(CALLERID(number)=${num})
exten => _+1.,3,Dial(H323/9${EXTEN:1}@PBX,130,tr)

exten => _+N.,1,AGI(2ldap.agi,tel:${CALLERID(num)},${EXTEN})
exten => _+N.,2,Set(CALLERID(number)=${num})
exten => _+N.,3,Dial(H323/9011${EXTEN:1}@PBX,130,tr)

[core]
exten => _X.,1,Set(CALLERID(number)=${num})
exten => _X.,2,Dial(H323/${EXTEN}@PBX,130,tr)

 

[busster]

The asterisk O'Reilly book is free to download.

It will explain all you ever wanted to know and more.

 

[busster]

In general:

exten = extension,priority,Command(parameters)

 

[phoneguy01]

Thanks