When Directory Numbers are created today and associated with an End User, either through LDAP Directory sync rule to Feature Group Template and DN Pool, but before a Device is connected and associated with that DN, the "Active" field is set to True (table numplan, field 'iscallable'=t) so that the number can be called and follow non-device specific features such as Fw > VoiceMail for the new user before any or all Devices are installed.
When one or more Devices is associated with the Directory Number, the Active (iscallable) field is hidden from the DN Configuration web form and replaced with the many-many list box showing one or more Devices associated with the DN.
Likewise, when Disassociating devices from the DN on the form, once the last associated device is removed, the form reverts to showing the Active (iscallable) field again. The DN remains callable at this point even though all the associated devices have been removed, and this is useful to provide, for example, a referral to a new number or alternate contact.
In Call Routing > Route Plan Report exists a search option in the Find drop-down called "Unassigned DN" > further search test > Find.
The suggested use of this Report is to perform housekeeping and select Directory Numbers that linger "detached", having had all their Devices disassociated, for deletion.
The resulting list from this Route Plan Report shows Patterns with null associated Devices in the Route Detail column. But the data returned does not consider or display the state of the "Active" (iscallable) field for the pattern.
As the feature works today, one can use the Select All button and Delete Selected (or the Delete All Found Items button) to delete the entire resulting list of patterns. But since no check or visibility is made for the iscallable flag, this can result in the unintended deletion of patterns that are either pre-staged for a new device deployment, or actively handling calls to a referral message post removal of the device(s).
One solution would be to only include rows in the in Unassigned DN search in which no associated Devices are located AND in which the pattern's iscallable state is False.
Or instead simply add a column to the form called "Active" probably located between existing Type and Route Detail columns to display the value of each pattern's iscallable field (read-only text "True/False", "Yes/No", "Enabled/Disabled" or greyed out selection box) so the Admin can make selections in the left-hand selection column for deletion being advised by the Active state, and either choose patterns for deletion individually or all as required.
When the displayed value is False, the pattern can be directly selected for deletion. When the displayed value is True, the Admin would presumably drill down into the pattern link's DN config page to research further.
Lastly, it would be extremely helpful to include the same new "Active" column to the Call Routing > Directory Number > Find Directory Number admin form also. Here, logically between the existing Description and Copy columns.