Connection Memory Low is a block of memory the same size as the Data Memory for the relative device (MT8980 or MT8981). Each byte in Connection Memory Low is associated with an output channel. Information can be placed into Connection Memory Low locations only through the microprocessor port, but it may exit in several directions: the information may be read by the microprocessor, form the address of a location in Data Memory (Switching mode) or be output in the associated ST-BUS output channel (Message mode). When the microprocessor is writing to or reading from Connection Memory Low, the address of the location being written to is formed by CRb2, CRb1, CRb0, A4, A3,

A2, A1, and A0. Either the Message mode or Switching mode function of the Connection Memory contents is performed automatically once per frame.

Connection Memory High appears to the microprocessor like Connection Memory Low did, in terms of size of the memory array, method of addressing and being able to be both read from and written to. Each byte of the Connection Memory High is associated with the same output channel as the related byte in the Connection Memory Low.