The UR-8FV is of the new CT/VT modules. It is characterized as having a standard 4CT/4VT. In contrast, other CT/VT modules may have either a standard or sensitive 8CT or a standard or sensitive 4CT/4VT with enhanced displays. The sensitive feature of some CT/VT modules allows them to provide the universal relays with ground fault protection. They have the capacity for this benefit by being able to acquire sensitive ground input in the case where there are grounded systems with high-impedance characteristics.  All of the CT/VT modules are able to provide the universal relays with up to 24 CT and VT signals (analog) to contribute to their monitoring ability of power lines. The additional special function modules can additionally detect faults that are caused by a downed conductor situation. It is important that the old CT/VT modules are placed in a universal relay that also has an older model CPU. Similarly it is important to match new CT/VT modules with new CPUs to avoid error indicators on the display. The older models will have lower alphanumeric codes following the RH-8 (ex. RH-8A).