[Asterisk-Users] Passing callerID info to a forwarded line

[Scott Laird]

On Nov 4, 2004, at 10:28 AM, Chris Goodwin wrote:
> Hi everyone,
>
> I have a question regarding the use of callerID and call forwarding.  
> When I forward any of my Zap extensions in the office to an outside 
> line, such as a cell phone, the callerID info shows up as originating 
> from that office phone, rather than from whoever actually originated 
> the call into that office phone.  Does anyone have an idea of how to 
> pass the callerID info of the originating caller to the forwarded 
> phone?

First, you need a connection to the PSTN that lets you set your own 
caller ID value.  POTS lines never have this.  PRIs may, depending on 
the configuration.  Some VoIP providers let you control the caller ID 
also; NuFone does, but I'm not sure about others.

Using NuFone, it's really easy--just send the call to them without 
resetting the caller ID value that you received on the incoming call.  
In my dial plan, I created a macro that calls SetCallerID with my own 
phone number if and only if the existing caller ID value is 4 or fewer 
digits long.  Here's an example:

[macro-condsetcid]
   exten => s,1,NoOp
   exten => s,2,GotoIf($[${CALLERIDNUM:0:4} = ${CALLERIDNUM}]?3:4)
   exten => s,3,SetCallerID(4254889999)
   exten => s,4,NoOp

Then, in my outbound dialing context, I just do 'Macro(condsetcid)' 
before doing 'Dial(${NUFONE}/${EXTEN})'.  Works perfectly.  There are a 
couple more examples at 
http://scottstuff.net/scott/archives/cat_asterisk.html


Scott