This reports the BUC's supply voltage, in tenths of a volt, over a range up to 64 volts. Because BUCs are typically fed 24 to 48 VDC over the coax cable, a voltage reading well outside the expected band points to a power supply problem or excessive cable voltage drop, distinct from the current-based fault detection. A reading of 480 (48.0V) on a BUC spec'd for 48VDC confirms healthy supply, while a drop to 380 (38.0V) under load could indicate a degrading power feed or long cable run.