A Communications Card is required in each CDSbus System utilizing an external controller. It is used to buffer command and data information received or transmitted by the CDSbus system. A Control Card is required in each mainframe to manage the flow of information on the backplane. When a CDSbus Interfaced Mainframe (IBX, RSX, CCX, or PIX) is ordered, the appropriate Communications Card and Control Card are supplied with the system.
A Chaining Card is required when multiple CDSbus Systems are to be controlled from one I/O port of the system controller or when any CCX is used.