The NTE4021B is a CMOS 8-bit integrated circuit, manufactured by NTE. It is a low power, low voltage device which is designed for high speed and low noise operation. It is ideal for applications such as interface expansion, communications, robotics, and embedded systems. The device features eight independent, fully parallel, six-bit bidirectional ports with various programmable options for control and direction, making it suitable for a variety of applications. The device also features an internal clock generator with three selectable frequencies, as well as input and output enables. Additionally, the power supply range is 3.0V to 6.5V, making it ideal for battery-powered applications.