| 摘要 |
A key-to-magnetic tape recorder is provided with multiple keyboard units to enable a plurality of operators to simultaneously supply input message blocks to a magnetic tape unit for recordation on a single magnetic tape. Each keyboard unit has a buffer memory for accumulating a single message block. A multiplexer having a transfer memory with a capacity for storing a plurality of message blocks sequentially polls the keyboard terminals and when a terminal having a completed message is encountered, polling is interrupted and the terminal transmits the message to the transfer memory over a common transmitting cable. The tape unit has a single-message block buffer memory and when the unit indicates that it is ready to record the next message block, a block is transferred from the transfer memory to the tape buffer memory. All block sections of the transfer memory share a common set of input lines, a common set of output lines and a single set of accessing circuits. Just prior to the time each polling request is transmitted to the terminals, the multiplexer controls inspect for the presence of at least a single message in the transfer memory and a message demand indication from the tape unit. If both these requirements are present, the polling operation is inhibited and a message is transferred out of the transfer memory. In this way unloading of the transfer memory takes priority over loading and maximum message transfer efficiency is accomplished with minimum hardware. Error control means automatically operate upon detection of certain types of transmission errors to reject the message and to notify the keyboard terminal from which the erroneous message was transmitted. Display means are provided for indicating the terminal origin of each message stored in the transfer memory and the tape unit buffer memory.
|
