12.88508 is a part of the Geyer Electronic family of Digital Input/Output Modules that are designed for distributed control systems. These DIN-rail mountable modules provide an economical and reliable, 8-point Digital Input/Output interface for various applications. They feature optically-isolated input channels, dc and ac power, and LEDs for indicating the status of each of the 8 channels. This part is highly resistant to electrical noise and is user programmable for adjustable hysteresis, as well as normal or inverted logic. It also offers versatility for connection to a variety of devices, such as analog signals, Thyristors, relays, or limit switches.