| 摘要 |
<p>A printer control system is disclosed for receiving data in the form of binary bits over a transmission line from a central processing unit, said data divided into characters to be printed, the control system comprises a rotary drum printer and a control circuit for directing the printer to print the characters. The control circuit has a storage means for receiving and storing the data, a drum trace means for providing an output and dependent upon the drum position, a comparator means for comparing, a character at a time, the data stored in the storage means with the drum position, a serial shift register for storing match and non-match signals between the data to be printed and the drum position and a trigger means for firing, after all stored characters have been compared with the drum position, those hammers of the printer which correspond to the matches between the data and the drum position. The characters are similarly compared to the next drum position and so on until the drum makes a complete revolution by which time all characters have been printed. In addition, the storage means comprises a memory which is divided into halves and the printer control circuit writes into one half the data received and prints the data stored in the second half and includes means for controlling into which half of the memory data is being written and out of which half data is being read.</p> |
