Wait on external event in DialPlan

Hi, using asterisk 1.6.2.8. Is it possible to wait on some external event in the DialPlan
Basically i want to do this

exten => 100,1,System(cmd)
exten => 100,2 Ringing
exten => 100,3, Waiton Event <- how to do this bit

then

exten = 100,4, Dial (SIP/2000)

ie when i get an external event , ring another extension

Thanks

what kind of external event?

Hi, thanks

The event is a user registering with Asterisk, so as soon as we know he’s registered we can then execute
the Dial instruction. The user will have his details set up in the sip.conf so Asterisk knows about him

Is there some event that is generated when a user registers, also how can the Dial plan wait on this.

Regards

Run AGi to check the user registration … and then use Dial simple.

Hi, we’ve been looking at the docs for the AGI but how do we check user registration via the AGI.
Also is it possible to do a sip reload via the AGI.

Thanks

Yes ofcorse, you can run asterisk console command in the AGI.

So if someone dials extensions 100, you want them to hold the phone waiting for some other device to register with Asterisk before the dial command will attempt to dial that device?

why not just dial them? your response to the device not being there should be something like a channel unaviable? the dialplan could then do something different based on that response.