[Asterisk-Users] Authenticating zap callers. (callerid or PIN code)

[Andrew Gillham]

Does anyone have any decent working examples of providing a means for a
remote caller to authenticate and get "internal" access through the PBX?

I would like to be able to call in with my cell (or any other line), enter
a code and then be able to dial just like if I had picked up my IP phone
at home.

My initial scenario would be letting me hit a number during my initial
announcement and then prompting (or just a subtle signal) for a certain 
code.
Once the code is entered successfully I would either just get a second dial
tone, or build an IVR to let me pick the function or service.

A second scenario might be to just look at the callerid and if it is my cell
to just throw the call right into the IVR or correct context, etc.

If anyone has a pointer to sample configs for this I would appreciate it.

-Andrew