An Altera Quartus II developer designs, simulates, and synthesizes digital logic designs. They use the Quartus II software to develop field-programmable gate array (FPGA) and application-specific integrated circuit (ASIC) designs. Their work includes creating schematic or text design entry, running design simulations to debug and verify the design, and performing timing analysis to ensure the system operates correctly under different conditions. They also handle the synthesis, placement, and routing of the design, and finally, they program the FPGA or ASIC device. The developer works closely with hardware engineers, ensuring the design meets all technical specifications.