The CT/VT modules used in universal relays come in a variety of order codes. A few CT/VT modules can be differentiated by the age of the order code. For example the 8A, 8B, 8C, and 8D are considered the original models. For some UR relays (such as the F35) the implication of having an older CT/VT module necessitates the CPU to be of the older model as well. If not there will just be an error code occurring across the display screen of the relay. The UR-8MH specifically has the sensitive ground 4CT/4VT with enhanced diagnostics. This additional sensitive ground option allows the universal relay to have protection from ground fault occurrences. Some order variations of the CT/VT modules do not come with this option.  The different CT/VT modules allow the end user to implement multiple unique schemes such as differential protection or concurrent split-phase schemes. The inter-relay communication module also facilitates communication in terms of analog values or digital status between the UR relays. Each variable option affords the end user with the ability to tailor their universal relay through a variety of order specifications to achieve a UR relay that is most applicable to their purpose at hand.