This is the control card for the Multifunction Controller.

The control card generates interrupt requests to the CPU, as well as performing on-line diagnostic functions for the parity check circuit and battery check circuit of memory card, and performs arithmetic functions.

The control card contains 16 LEDs mounted at the card edge for indication of diagnostic status. All LEDs should be on during normal operation. DS15 will blink when the MC is in idle mode, and DS16 will flash when MC is in processing mode. Any blank LEDs is an indication of a failure and should be diagnosed using the corresponding LBOS Diagnostic Display Codes.