Wireshark-users: [Wireshark-users] DPNSS dissector C/R bit

From: "Keith French" <keithfrench@xxxxxxxxxxxxx>
Date: Wed, 7 Oct 2009 15:11:36 +0100
DPNSS uses the Command / Response bit from Octet 1 of the Address field to determine the direction of the layer 2 frame from either PBX A or PBX B.
 
If the C/R bit is set to 1 this indicates a Command frame from PBX A, or a Response frame from PBX B.
If the C/R bit is set to 0 this indicates a Command frame from PBX B, or a Response frame from PBX A.
 
I am trying to add a custom column to show the direction of Command frames, if I use the filter:-
 
dpnss_link.crbit
The column just shows:-
 
"Command/Response bit set" or "Command/Response bit cleared".
 
Is there a way I can add a direction column that would just show "PBX A" or "PBX B"?