Do I need to change my Customer Data Block RDR_DATA OPT? 

First, print yours:

>LD 21

REQ PRT
TYPE RDR
 

In "OPT" look for CFF or CFO. 

Change

>LD 15
REQ CHG
TYPE RDR
at OPT, enter "CFF" or "CFO" - whichever you deem appropriate. 

For the Impatient: You want OPT CFF if you want users to Call Forward "external".

Here are examples of CFF/CFO in action with Call Forward External:

If you have CFO.  Notice how the NCOS is obtained from the trunk - and the CFW is blocked.

Caller --> Trunk(NCOS 0) --> Telephone(NCOS 3) on CFW --> BLOCKED - NCOS too low

If you have CFF.  Notice how the NCOS is obtained from the forwarded telephone (this setting enables external Call forward)

OPT CFF = Obtain CLS and NCOS of the CFW'ing TN when determining restrictions. 

Caller --> Trunk(NCOS 0) --> Telephone(NCOS 3) on CFW --> CFW to External

Link to this page: http://www.ghtrout.net/rdr/cff-cfo.html