I have a customer who wants their DNIS digits for DID to display on the phones that ring on that number (ring group) so they know it's a call on that number. I copied the existing COS to a new one and applied to those 6 sets and changed "Display ANI/ISDN Calling Number Only" to disabled thinking that would display the DNIS digits before the call is answered, but it still just shows the Caller ID information in the display of all the phones.
What am I missing to make it just show the DNIS until the call is answered, then show the Caller ID/ANI? This is on a PRI with 53xx sets.