Emerson COM Express Carrier Design Manual page 84

Figure 33 GPIO Loop-Back Schematic
 There are four GPI (general purpose inputs) and four GPO (general purpose outputs) pins in Figure
33. These signals drive switch inputs such as lamps, relays, and sensors.
 GPI signals from a header are shown with protection diodes. The signals are connected for input to
the COM Express module.
 GPO signals from the COM Express module are shown buffered. The signals are connected to the
header with protection diodes.
Page 84 of 103 COM Express Carrier Type 2
Design Guide