The B30 bus differential relay has a horizontal unit B30 base with the following order code breakdown: B30-***-***-F**-H**-L**-N**-S**-U**-W/X**. The first triad alphanumeric code for the B30 in question is G00. This shows that the B30 has the G order code for a CPU module. The CPU is described with the RS485 and multi-mode ST 10Base-F communication description. Following B30-G00- is the HCH designation. This order code specifies the type of mount (horizontal 19 inch rack), the type of faceplate/display (C is an English display), and the power supply. In this case the power supply is a 125/250 V AC/DC power supply. In the case where a universal relay contains two power supply modules (main and redundant) then both power supply modules must be of the same order code. The F8F option begins the hardware specifications. In this case the CT/VT module included is the standard 4CT/4VT option. The H** (H6P) describes the digital input/output module as a 6P option with 6 Form-A outputs and four digital inputs (with optional voltage monitoring). When XX is included at a order location this means that there is no module at that locus. The N6P is another 6P order code digital I/O module, and the U5F describes a transducer I/O with 8 dcmA inputs.