IODs and SOP Classes define Type 1 Data Elements that shall be included and are mandatory elements. The Value Field shall contain valid data as defined by the elements VR and VM as specified in PS 3.6. The Length of the Value Field shall not be zero. Absence of a valid Value in a Type 1 Data Element is a protocol violation.

Note: For data elements with a string (CS, SH, LO) rather than binary, text or sequence Value Representation, and for which multiple Values are allowed, the presence of a single Value is sufficient to satisfy the Type 1 requirement, unless specified otherwise in the Attribute description, and other Values may be empty, unless otherwise specified by the IOD. The presence of one or more delimiter (BACKSLASH) characters alone, without any Values, is not sufficient to satisfy the Type 1 requirement, since even though the Value Length is greater than zero, there is no valid Value present.