How can i get the call ID?

If for example, the SIP/206 is ringing…
From my phone 233, how can i set the call id of SIP/206?

Ex: From my phone, SIP/233
exten=>00,2,Set(TheID=Here the SIP id of SIP/206)

I want set the output of the var something like this: SIP/206-00000057

How can i?

Please ask on Asterisk Support. Hint: this is not the call ID, or ever the caller ID.