| 摘要 |
A communication method and digital multi-customer data interface for interconnecting a number of customer terminals to a main packet switching network of a local area data transport system that provides data communication services such as interactive video text service between data service vendors and customers. The digital multi-customer interface utilizes a main processor, control circuit, and multi-customer protocol controller to implement the protocol functions for the communication of packets and control information over individual serial transmission paths. The multi-customer protocol controller comprises a control processor and a formatter circuit for synchronously communicating packets for a plurality of customer terminals via customer line units and customer lines. The control circuit handles communication of all control and status information between the main processor and the customer line units. The control circuit communicates control and status information with customer line interface units over serial transmission paths by selecting one unit at a time for transmission. Erroneous transmissions by a malfunctioning unit which has not been selected for transmission are detected by using an error generator to monitor all transmission lines and by controlling the generated error type with data from the selected unit. Unless a predefined error type is generated, an error indication is given since an erroneous transmission has occurred.
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