[Asterisk-Users] Able to tell if phone is registered?

[Nathan C. Smith]

Hi All,

I have a new asterisk setup running at home and am very happy with it. 
One thing that I am trying to do is to take various actions in the 
dialplan *if* a particular phone is registered/authenticated/connected. 
For example, if someone dials *me* and is shows that I am connected via 
my softphone, to try it instead of my deskphone (and possibly notifiy 
the user in advance that it is taking that action).

There are a couple ways, but within the dialplan you can use chanavail().
On the console you can type "show application appname" to get more
information about applications such as chanavail and dial.  

On the failure of a dial command the priority jumps 101, so for instance if
you softphone was dialed at priority 3 and it failed the execution would
jump to priority 104 where you could attempt to dial your deskphone.

Finally, you can use the asterisk database.  By dialing an extension to set
a database value and checking for a value in the dialplan you can use logic
to decide whether to dial an extension or not.

Most of this is documented reasonably well on www.voip-info.org once you
know what you are looking for.

-Nate