VCC (Voltage Common Collector) is the higher voltage with respect to GND (ground). VCC is the power input of a device. It may be positive or negative with respect to GND. When the only positive power supply is used then VSS (Voltage Source Supply) means ground or zero. The Intel 8085 Microprocessor needs a power supply of +5 V DC for its working. Pin 40 of Intel 8085 is the Vcc pin. It should be connected to +5 V DC power supply. Pin 20 of 8085 is the Vss pin.