Patent ID: 7688476

Claim:
A data transfer system for transmitting and receiving image data and control characters across an interface for output to a printer, the system comprising: a transmitter device for transmitting image data, in packets bits being of a packet size less than a line of image data, and control characters along a 16-bit CRC value for each packet across an interface; a receiver device for receiving transmitted image data and control characters; and a controller for determining, at a bit level, whether or not a packet of image data has been sufficiently transferred to said receiver device and if determining that the current packet of image data bits has not been sufficiently transferred, said controller provides for output to the printer of a prior sufficiently received line of image data in replacement of the current packet of image data so that the prior line of sufficiently received image data is printed at least twice in succession the controller is programmed to provide a determination related to increases over time of failures to sufficiently transmit lines and/or packets of image data across the interface of the need for maintenance and provides a signal related to such need, and a display for indicating the need for a service call or maintenance in response to said signal.