When does "Description" in CRT apply?

[Dogbreath]

Migrated site's trunks from PRI to SIP. Users are complaining that the "Description" label in the call routing table entry no longer shows on the callee's phone when a call comes in.
PRI has been ceased so I have no way to compare, but equally I have no reason to doubt what the customer is saying.
I have attempted to compare the CO Trunk Group and the SIP Trunk Group but they don't really have a lot of settings in common. Everything that is common between them is the same.
System software is 6.0SP3.
What conditions are required for the Description to appear on the callee's phone?

[Tech Electronics]

Dogbreath,

Most likely the flag [Outside Party Call Information Has Priority] has been enabled on the users phones. If it isn't enabled then they would get the description associated with the DID/DDI.

Thanks,

TE

[Dogbreath]

Thanks TE, that's the one. I suspect it has nothing to do with migrating off ISDN, it's that they hadn't noticed previously.