MESSAGE-ORIENTED BANK CONTROLLER INTERFACE

Disclosed is a message oriented interface for communication between a Bank Controller Unit and peripheral devices, such as channel units, in digital l oop transmission systems. At least four registers are used for each peripheral devic e. Two registers are utilized to transmit control signals, and two registers are fo r data transmission. An additional data register can hold the last byte read by the Ban k Controller Unit in the event of an error so the byte can be re-read. The last by te of each message, which is utilized for error detection, is the exclusive OR functio n of the corresponding bits in all the previous bytes of the message. A service reque st can be asserted by a peripheral device to the Bank Controller Unit when a contro l signal is present in one of the registers. Means are also provided for indicatin g when a register is busy.