RT Essentials

Custom fields (also known as CFs) are application-specific metadata that are created specifically for the local RT installation.

Starting with RT 3.4, custom fields can be applied to tickets, transactions on tickets, users, and groups. Each custom field can apply to only one type of object. Ticket and transaction custom fields can be tied to any number of queues, but user and group custom fields apply system-wide.

Custom fields can be one of several types:

Select

A Select field has a predetermined set of values. For example, a CF containing a list of computer operating systems supported by the Help Desk would very likely be a Select CF.

Freeform

Freeform fields contain single lines of text.

Text

Text fields hold multi-line blocks of plain text.

Wikitext

Text fields hold multi-line blocks of wiki text.

Binary

Binary fields are uploaded files.

Image

Image fields are like Binary files, but they are displayed on the Web UI instead of presented as download links.

In addition to its type, a custom field also has a MaxValue setting that limits the number of its entries. As of this writing, the web configuration interface only allows 1 (Single fields) and 0 (Multiple fields).