This is the cable interface card for the Multifunction Controller, PIUs, and DHP. It has BNC connectors on the card edge to connect the hiway A and B cables to these devices.

The function of this card upon receiving data is to accept data from the Hiway, check its validity, and pass it along to the Hiway DMA card for additional processing. For transmission of data, this card adds the BCH code, then transmits the data on the Hiway.

This card has 2 LEDs, which when illuminated indicate the active Hiway, A or B.