Many newer PCs and laptop computers do not have any DB9-type RS232 serial ports. They are only equipped with USB ports.
Although Hitachi does not offer inverters above 3 hp specifically sized and rated for single-phase operation, single-phase power can be safely used with larger 3-phase rated inverters, provided that care is taken to properly upsize and apply the inverter.
When applying an inverter to centrifugal compressors on HVAC chillers, there are a number of factors to consider.
First and foremost, IEEE-519-1992 describes the RECOMMENDED Practices and Requirements for Harmonic Control in Electrical Power Systems.