Abstract: Errors occurring in information signals (each including control signals), dummy codes and attribute flags for the information signals and the dummy codes, transferred from a transmitting circuit to a receiving circuit through an interface line, with frames arranged in a serial transfer form are detected by using a cyclic redundancy check (CRC). The dummy codes and attribute flags for the dummy codes are not used in this checking. The re-transmission of signals in the frame resulting from a CRC error generated by the attribute flag for the dummy code changing to that of a control signal in the frame is avoided by: (1) providing, at the transmitting circuit, flags for determining the existence and the number of the control signal in the frame in front of the succeeding frame, and (2) comparing signals, relating to the flags, detected in the receiving circuit with the flags.

Abstract: In order to constitute means for reliably separating sheets positioned at the lowermost level in a magazine one by one, there are provided two stages of main and auxiliary side hooks which can be rocked in the direction for supporting the sheets and in the direction for releasing the same as operated inversely to the seam hooks, on the both left and right sides of the magazine so that the side hooks can be rocked in correlation with suction arms, each of the respective side hooks has its supporting position for the sheets made variable, and the side hooks are adjustably disposed so that the interval between the side hooks on the left and right sides of the magazine can be varied with the main and auxiliary side hooks on each side held integrally.