The 62S11-H9-P is a compact 1/2" optical encoder from Grayhill designed for rotary position sensing in applications requiring minimal behind-panel space. It features a 2-bit quadrature output with channel A leading channel B by 90° electrically during clockwise rotation, open-collector phototransistor outputs requiring external pull-up resistors, and an optional integral pushbutton switch. The encoder operates at 5.00 ±0.25 VDC with a maximum supply current of 25 mA, delivers logic high output of no less than 3.8 VDC and logic low of no greater than 0.8 VDC, and is rated for 1 million rotational cycles for low and medium torque applications (500,000 cycles for high torque, 3 million for non-detent styles). It withstands an operating temperature range of -40°C to 85°C, mechanical vibration of 15 g (10–2000 Hz), and mechanical shock of 100 g (6 ms), making it suitable for global positioning systems, driver information systems, and medical equipment requiring reliable rotary feedback in compact installations.