P-Asserted-Identity (PAI) is now a common requirement to allow the mapping of A-Party IDs through to the C-Party when being transferred (by B-Party). I.e. A call comes in from 027123456 (A-Party) to your company desk phone (B-Party). If you are re-directing all calls to your mobile phone with PAI you will now see the A-Party number (027123456) as the incoming caller ID on your mobile rather than your company pilot number or DDI.

NOTE: In the below samples entries listed in UPPER CASE are user set names & can be customised according to your requirements

  First, add the mapping tables into a complex function:  


context cs switch
routing-table called-e164 ISDN-TO-SIP

mapping-table calling-pi to calling-pi MAP-PI
    map allowed to allowed
    map restricted to restricted
    map interworking to interworking
    map default to allowed

mapping-table calling-si to calling-si MAP-SI
map default to network

complex-function FCN-MAP
execute 1 MAP-PI
execute 1 MAP-SI 


The apply the newly created complex function 'FCN-MAP' to your outbound route:

  routing-table called-e164 ISDN_TO_SIP
    route default dest-interface SNAP_SIP_IF FCN-MAP

Lastly, enable privacy on the SIP interface: 

  interface sip MyITSP_SIP_IF


You should be able to check your work using Wireshark

The final destination phone should ring & show the Caller-ID of the PAI section i.e. the original calling party.